Rat hepatitis E virus (Rocahepevirus ratti) exposure in cats and dogs, Hong Kong

Hepatitis E virus (HEV) variants infecting humans belong to two species: Paslahepevirus balayani (bHEV) and Rocahepevirus ratti (rat hepatitis E virus; rHEV). R. ratti is a ubiquitous rodent pathogen that has recently been recognized to cause hepatitis in humans. Transmission routes of rHEV from rats to humans are currently unknown. In this study, we examined rHEV exposure in cats and dogs to determine if they are potential reservoirs of this emerging human pathogen. Virus-like particle-based IgG enzymatic immunoassays (EIAs) capable of differentiating rHEV & bHEV antibody profiles and rHEV-specific real-time RT-PCR assays were used for this purpose. The EIAs could detect bHEV and rHEV patient-derived IgG spiked in dog and cat sera. Sera from 751 companion dogs and 130 companion cats in Hong Kong were tested with these IgG enzymatic immunoassays (EIAs). Overall, 13/751 (1.7%) dogs and 5/130 (3.8%) cats were sero-reactive to HEV. 9/751 (1.2%) dogs and 2/130 (1.5%) cats tested positive for rHEV IgG, which was further confirmed by rHEV immunoblots. Most rHEV-seropositive animals were from areas in or adjacent to districts reporting human rHEV infection. Neither 881 companion animals nor 652 stray animals carried rHEV RNA in serum or rectal swabs. Therefore, we could not confirm a role for cats and dogs in transmitting rHEV to humans. Further work is required to understand the reasons for low-level seropositivity in these animals.

Effects of irisin and exercise on adropin and betatrophin in a new metabolic syndrome model

Metabolic syndrome (MetS) is a prevalent public health problem. Uric acid (UA) is increased by MetS. We investigated whether administration of UA and 10% fructose (F) would accelerate MetS formation and we also determined the effects of irisin and exercise. We used seven groups of rats. Group 1 (control); group 2 (sham); group 3 (10% F); group 4 (1% UA); group 5 (2% UA); group 6 (10% F + 1% UA); and Group 7, (10% F + 2% UA). After induction of MetS (groups 3 -7), Group 3 was divided into three subgroups: 3A, no further treatment; 3B, irisin treatment; 3C, irisin treatment + exercise. Group 4, 1% UA, which was divided into three subgroups: 4A, no further treatment; 4B, irisin treatment; 4C, Irisin treatment + exercise. Group 5, 2% UA, which was divided into three subgroups: 5A, no further treatment; 5B, irisin treatment; 5C, irisin treatment + exercise. Group 6, 10% F + 1% UA, which was divided into three subgroups: 6A, no further treatment; 6B, irisin treatment; 6C, irisin treatment + exercise. Group 7, 10% F + 2% UA, which was divided into three subgroups: 7A, no further treatment; 7B, irisin treatment; 7C, irisin treatment + exercise., İrisin was administered 10 ng/kg irisin intraperitoneally on Monday, Wednesday, Friday, Sunday each week for 1 month. The exercise animals (in addition to irisin treatment) also were run on a treadmill for 45 min on Monday, Wednesday, Friday, Sunday each week for 1 month. The rats were sacrificed and samples of liver, heart, kidney, pancreas, skeletal muscles and blood were obtained. The amounts of adropin (ADR) and betatrophin in the tissue supernatant and blood were measured using an ELISA method. Immunohistochemistry was used to detect ADR and betatrophin expression in situ in tissue samples. The duration of these experiments varied from 3 and 10 weeks. The order of development of MetS was: group 7, 3 weeks; group 6, 4 weeks; group 5, 6 weeks; group 4, 7 weeks; group 3, 10 weeks. Kidney, liver, heart, pancreas and skeletal muscle tissues are sources of adropin and betatrophin. In these tissues and in the circulation, adropin was decreased significantly, while betatrophin was increased significantly due to MetS; irisin + exercise reversed this situation. We found that the best method for creating a MetS model was F + UA2 supplementation. Our method is rapid and simple. Irisin + exercise was best for preventing MetS.

The time interval between injection of nicotine and tremor initiation: a new index for evaluating nicotine efficacy in rodents

Tremor is one of the effects of nicotine as a toxic substance, especially in animal models. The intensity and duration of tremors were used to evaluate the effect of nicotine on locomotor activity in laboratory animals. In our observations, the time interval between nicotine injection and the onset of tremor changed depending on the dose. Therefore, by increasing the dose of nicotine in rats, the time interval of tremor onset was also shortened. These results suggest that the time interval between nicotine injection and the onset of tremors can be used as a complementary index for better evaluation of nicotine-derived motor disturbances.

Unraveling the immune response of the spleen in sepsis using green-synthesized silver nanoparticles from pomegranate peel extracts

Sepsis is a serious disease characterized by an inappropriate host response to infection, resulting in widespread inflammation and systemic organ failure. The aim of this research is to investigate the possibility of pomegranate peel-derived silver nanoparticles (PGNP) as a potential alternative therapy for sepsis. Characterization using transmission electron microscopy revealed 10-30 nm spherical nanoparticles. In a rat model of sepsis, PGNP treatment improved spleen health, histology, and immune response as compared with septic rats. In rats treated with PGNP during sepsis, significant alterations in oxidative stress markers (p < .01) were observed. These included elevated levels of glutathione (0.63 ± 0.08 mmol/mg protein), reduced concentrations of nitric oxide (8.7 ± 0.8 μ mol/mg protein) and malondialdehyde (2.2 ± 0.3 nmol/mg protein), as well as increased activity of superoxide dismutase (159 ± 33 U/mg protein). Following PGNP administration, gene expression analysis revealed a decrease in spleen IL-1β, IL-6, and TNF-α, highlighting its anti-inflammatory potential. Furthermore, PGNP effectively controlled apoptosis-related genes (Bax, Bcl-2, and Casp3), indicating its role in cellular survival pathways. This study sheds light on the immunological regulation of the spleen during sepsis using PGNP, demonstrating its potential as a new effective treatment approach. The study emphasizes the necessity of continuing to investigate and develop alternative medicines, particularly in light of antibiotic resistance and the global impact of sepsis. RESEARCH HIGHLIGHTS: The study explored the potential medicinal benefits of pomegranate peel-derived silver nanoparticles (PGNP) in the treatment of sepsis. PGNP suppressed pro-inflammatory cytokines and enhanced the immune response. The study recommends PGNP as a viable substitute treatment.

Metabolic and ultrastructural renal changes in adult Wistar rats fed by a cafeteria diet

PURPOSE

To evaluate, by quantitative and qualitative methods, the glomerular ultrastructure in Wistar rats fed a cafeteria diet.

METHODS

Male Wistar rats were divided into two groups at 21 days of age: control (C, n = 10) and cafeteria diet (CAF, n = 8). The animals were followed up until 5 months of age, followed by euthanasia. The blood, kidneys, and fat deposits--epididymal, retroperitoneal, and subcutaneous--were extracted and analyzed. Data were analyzed by Student's t test, and p < 0.05 was considered statistically significant.

RESULTS

The cafeteria diet promoted glucose intolerance, hyperglycemia (p < 0.0001), and deposition of retroperitoneal fat (p < 0.005). Scanning electron microscopy revealed that the length of the foot process was similar in both groups. The quantitative analyses by transmission electron microscopy revealed that the cafeteria diet reduced the thickness of the glomerular basement membrane (p < 0.05).

CONCLUSIONS

The intake of lipids and simple carbohydrates were found to be associated with alteration in the glomerular ultrastructure. However, more studies are needed to evaluate not only the effects of high-protein and high-fat diets on components of the glomerular filtration barrier, but also renal physiology.

E-cadherin and NF-κB expression in the vagina after ovarian ischemia and reperfusion

PURPOSE

To investigate inflammation and cell adhesion molecules in the vagina after ovarian ischemia-reperfusion (IR) injury.

METHODS

20 Wistar albino female rats were divided into two groups: control, and IR groups. In IR group, blood flow was restricted for 2 hours for ovarian ischemia. Then, tissues were re-blood 2 hours for reperfusion. Vagina tissues were excised and processed for histopathological analysis. Histopathological and biochemical follow-ups were performed.

RESULTS

Both malondialdehyde and myeloperoxidase values were increased in IR group compared to control group. Glutathione content was decreased in IR group compared to control group. Epithelial degeneration, inflammation, dilatation, and nuclear factor-κB (NF-κB) expression were increased in IR group compared to control group. E-cadherin expression was significantly decreased in IR group. In the IR group, E-cadherin showed a positive reaction in adenomas, gland-like cryptic structures, cellular junctions with clustered inflammatory cells. In the IR group, NF-κB expression was increased in basement membrane, inflammatory cells, in blood vessels.

CONCLUSIONS

Ovarian ischemia caused degeneration of epithelial cells in the vaginal region and disruptions in the cell junction complex, which leads to activation of E-cadherin and NF-κB signaling pathway and alterations in reproductive and embryonal development in the vaginal region.

Prelimbic Cortex-Nucleus Accumbens Core Projection Positively Regulates Itch and Itch-Related Aversion

Itch is one of the most common clinical symptoms in patients with diseases of the skin, liver, or kidney, and it strongly triggers aversive emotion and scratching behavior. Previous studies have confirmed the role of the prelimbic cortex (Prl) and the nucleus accumbens core (NAcC), which are reward and motivation regulatory centers, in the regulation of itch. However, it is currently unclear whether the Prl-NAcC projection, an important pathway connecting these two brain regions, is involved in the regulation of itch and its associated negative emotions. In this study, rat models of acute neck and cheek itch were established by subcutaneous injection of 5-HT, compound 48/80, or chloroquine. Immunofluorescence experiments determined that the number of c-Fos-immunopositive neurons in the Prl increased during acute itch. Chemogenetic inhibition of Prl glutamatergic neurons or Prl-NAcC glutamatergic projections can inhibit both histaminergic and nonhistaminergic itch-scratching behaviors and rectify the itch-related conditioned place aversion (CPA) behavior associated with nonhistaminergic itch. The Prl-NAcC projection may play an important role in the positive regulation of itch-scratching behavior by mediating the negative emotions related to itch.

A novel reuptake inhibitor, IP2015, induces erection by increasing central dopamine and peripheral nitric oxide release

BACKGROUND AND PURPOSE

An estimated 40% of patients with erectile dysfunction have a poor prognosis for improvement with currently available treatments. The present study investigated whether a newly developed monoamine transport inhibitor, IP2015, improves erectile function.

EXPERIMENTAL APPROACH

We investigated the effects of IP2015 on monoamine uptake and binding, erectile function in rats and diabetic mice and the effect on corpus cavernosum contractility.

KEY RESULTS

IP2015 inhibited the uptake of 5-HT, noradrenaline and dopamine by human monoamine transporters expressed in cells and in rat brain synaptosomes. Intracavernosal pressure measurement in anaesthetized rats revealed that IP2015 dose-dependently increased the number and the duration of spontaneous erections. Whereas pretreatment with the dopamine D2-like receptor antagonists, clozapine and (-)-sulpiride, or cutting the cavernosal nerve inhibited IP2015-induced erectile responses, the phosphodiesterase type 5 inhibitor sildenafil further enhanced the IP2015-mediated increase in intracavernosal pressure. IP2015 also increased the number of erections in type 2 diabetic db/db mice. Direct intracavernosal injection of IP2015 increased penile pressure, and in corpus cavernosum strips, IP2015 induced concentration-dependent relaxations. These relaxations were enhanced by sildenafil and blunted by endothelial cell removal, a nitric oxide synthase inhibitor, NG-nitro-l-arginine and a D1-like receptor antagonist, SCH23390. Quantitative polymerase chain reaction (qPCR) showed the expression of the dopamine transporter in the rat corpus cavernosum.

CONCLUSION AND IMPLICATIONS

Our findings suggest that IP2015 stimulates erectile function by a central mechanism involving dopamine reuptake inhibition and direct NO-mediated relaxation of the erectile tissue. This novel multi-modal mechanism of action could offer a new treatment approach to erectile dysfunction.

Attitudes of clients of Dutch pest controllers towards integrated pest management (IPM) and preventive measures in relation to rodent nuisance

BACKGROUND

Rodent management with lethal methods (e.g., rodenticides) comes with downsides for rodent welfare, the environment and non-target species. To reduce chemical use and prevent rodent nuisance, pest controllers in the Netherlands must work according to the principles of integrated pest management (IPM). A condition for the success of IPM is that there is sufficient engagement of all parties involved, including clients of pest controllers. The aim of this study was to gain insight into the attitudes of clients regarding rodent control, IPM and the application of preventive measures. Insight into their attitudes may contribute to a better implementation of IPM and with that to a more sustainable rodent management based on more effective prevention. An online survey among 248 clients of Dutch pest controllers from both the agricultural and other sectors was carried out.

RESULTS

Respondents from the agricultural sector had a relatively negative attitude towards IPM, the new IPM regulations in the Netherlands and had little confidence in prevention. In other sectors, respondents were more positive about IPM and had more confidence in prevention. The respondents from the latter subgroup had a similar attitude compared to Dutch pest controllers who participated in a previous survey.

CONCLUSION

The findings of the study provide information for the further development and practical implementation of IPM and preventive measures and with that a more sustainable and animal friendly rodent management. They can also be helpful for a better communication and cooperation between pest controllers and their clients. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Therapeutic benefit of oregano oil in the acute idiosyncratic hepatotoxicity induced by carbon tetrachloride in rats: Adverse effects of high dose of oreganum

Toxicity caused by carbon tetrachloride (CCl4) can lead to serious liver injury. The aim of the study is to investigate the protective effects of oregano oil (Origanum minutiflorum extract oil) against CCl4-induced liver injury. Two doses of oregano oil were used in the experiment: a low dose (LD; 20 mg/kg) and a high dose (HD; 60 mg/kg) during 2 weeks. CCl4 caused severe liver damage, nucleolus destruction in hepatocytes and cytogenetic changes in the nucleus. Indirectly, CCl4 causes decreased protein synthesis and significantly high creatinine and urea values. Hematological disorders have been recorded, such as decreased RBC and hemoglobin concentration, increased WBC and deformability of the erythrocyte membrane. Both doses of oregano oil had protective effects. Improved protein synthesis and high globulins level, creatinine and urea were found in both groups. Cytogenetic changes in the nucleus of hepatocytes were reduced. A high dose of oregano oil had maximal protective effects for RBC, but a very weak effect on hemoglobin synthesis. Also, WBC and lymphocyte values were low. Origanum stimulates protein synthesis and recovery of hepatocytes after liver injury, reduces the deformability of the erythrocyte membrane. High doses of oregano oil decreased WBC and lymphocytes which may lead to a weakening of the immune response. However, high doses are more effective against severe platelet aggregation than low doses, suggesting an effective treatment against thrombocytosis.

Safety assessment of transgenic maize CC-2 by 90-day feeding study in Sprague-Dawley rats

Objective

The purpose of this study was to assess the safety of transgenic maize CC-2 through a 90-day feeding study in Sprague-Dawley rats.

Methods

Transgenic maize CC-2 and its parental counterpart maize Zhengdan 958 were respectively incorporated into diets at levels of 70%, 35% or 17.5% (w/w) and were administrated to rats (n = 10/sex/group) for 90 days. An additional control group of rats (n = 10/sex/group) were fed with the AIN93 breeding diet. All formulated diets were nutritionally balanced.

Results

There was no death and obvious toxic symptom in all rats. Food consumption, body weight, total food consumption rate, hematology, urinalysis, organ weight and organ coefficient were comparable between transgenic groups and the corresponding dose parental groups. There were significant differences of food consumption rate on some timepoint between high dose transgenic group and high dose parental group; male rats in high dose transgenic group showed significantly higher ALT/AST than high dose parental group on the middle or end of the experiment; but the differences showed no biological significance. There were no significant differences of other serum biochemistry parameters and pathological changes.

Conclusion

The results in this study demonstrated that the transgenic maize CC-2 didn't cause any related toxicity in rats.

PEDF peptide plus hyaluronic acid stimulates cartilage regeneration in osteoarthritis via STAT3-mediated chondrogenesis

Aims

Pigment epithelium-derived factor (PEDF) is known to induce several types of tissue regeneration by activating tissue-specific stem cells. Here, we investigated the therapeutic potential of PEDF 29-mer peptide in the damaged articular cartilage (AC) in rat osteoarthritis (OA).

Methods

Mesenchymal stem/stromal cells (MSCs) were isolated from rat bone marrow (BM) and used to evaluate the impact of 29-mer on chondrogenic differentiation of BM-MSCs in culture. Knee OA was induced in rats by a single intra-articular injection of monosodium iodoacetate (MIA) in the right knees (set to day 0). The 29-mer dissolved in 5% hyaluronic acid (HA) was intra-articularly injected into right knees at day 8 and 12 after MIA injection. Subsequently, the therapeutic effect of the 29-mer/HA on OA was evaluated by the Osteoarthritis Research Society International (OARSI) histopathological scoring system and changes in hind paw weight distribution, respectively. The regeneration of chondrocytes in damaged AC was detected by dual-immunostaining of 5-bromo-2'-deoxyuridine (BrdU) and chondrogenic markers.

Results

The 29-mer promoted expansion and chondrogenic differentiation of BM-MSCs cultured in different defined media. MIA injection caused chondrocyte death throughout the AC, with cartilage degeneration thereafter. The 29-mer/HA treatment induced extensive chondrocyte regeneration in the damaged AC and suppressed MIA-induced synovitis, accompanied by the recovery of cartilage matrix. Pharmacological inhibitors of PEDF receptor (PEDFR) and signal transducer and activator of transcription 3 (STAT3) signalling substantially blocked the chondrogenic promoting activity of 29-mer on the cultured BM-MSCs and injured AC.

Conclusion

The 29-mer/HA formulation effectively induces chondrocyte regeneration and formation of cartilage matrix in the damaged AC.

Atlas of Cell Repertoire Within Neointimal Lesions Is Metabolically Altered in Hypertensive Rats

BACKGROUND

High blood pressure has been suggested to accelerate vascular injury-induced neointimal formation and progression. However, little is known about the intricate relationships between vascular injury and hypertension in the context of arterial remodeling.

METHODS

Single-cell RNA-sequencing analysis was used to depict the cell atlas of carotid arteries of Wistar Kyoto rats and spontaneously hypertensive rats with or without balloon injury.

RESULTS

We found that hypertension significantly aggravated balloon injury-induced arterial stenosis. A total of 36 202 cells from carotid arteries with or without balloon injury were included in single-cell RNA-sequencing analysis. Cell composition analysis showed that vascular injury and hypertension independently induced distinct aortic cell phenotypic alterations including immune cells, endothelial cells (ECs), and smooth muscle cells. Specifically, our data showed that injury and hypertension-induced specific EC phenotypic alterations, and revealed a transition from functional ECs to hypermetabolic, and eventually dysfunctional ECs in hypertensive rats upon balloon injury. Importantly, our data also showed that vascular injury and hypertension-induced different smooth muscle cell phenotypic alterations, characterized by deferential expression of synthetic signatures. Interestingly, pathway analysis showed that dysregulated metabolic pathways were a common feature in monocytes/macrophages, ECs, and smooth muscle cells in response to injury and hypertension. Functionally, we demonstrate that inhibition of mitochondrial respiration significantly ameliorated injury-induced neointimal formation in spontaneously hypertensive rats.

CONCLUSIONS

This study provides the cell landscape changes of the main aortic cell phenotypic alterations in response to injury and hypertension. Our findings suggest that targeting cellular mitochondrial respiration could be a novel therapeutic for patients with hypertension undergoing vascular angioplasty.

Hepatoprotective activity of Lactéol® forte and quercetin dihydrate against thioacetamide-induced hepatic cirrhosis in male albino rats

Liver cirrhosis is a silent disease in humans and is experimentally induced by many drugs and toxins as thioacetamide (TAA) in particular, which is the typical model for experimental induction of hepatic fibrosis. Thus, the objective of the present study was to elucidate the possible protective effects of lactéol® forte (LF) and quercetin dihydrate (QD) against TAA-induced hepatic damage in male albino rats. Induction of hepatotoxicity was performed by TAA injection (200 mg/kg I/P, twice/ week) in rats. LF (1 × 109 CFU/rat 5 times/week) and QD (50 mg/kg 5 times/week) treated groups were administered concurrently with TAA injection (200 mg/kg I/P, twice/ week). The experimental treatments were conducted for 12 weeks. Hepatotoxicity was evaluated biochemically by measuring alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT) in the serum and histopathologically with the scoring of histopathological changes besides histochemical assessment of collagen by Masson's trichrome and immunohistochemical analysis for α-smooth muscle actin (α-SMA), Ki67 and caspase-3 expression in liver sections. Our results indicated that LF and QD attenuated some biochemical changes and histochemical markers in TAA-mediated hepatotoxicity in rats by amelioration of biochemical markers and collagen, α-SMA, Ki67 and caspase3 Immunoexpression. Additionally, LF and QD supplementation downregulated the proliferative, necrotic, fibroblastic changes, eosinophilic intranuclear inclusions, hyaline globules and Mallory-like bodies that were detected histopathologically in the TAA group. In conclusion, LF showed better hepatic protection than QD against TAA-induced hepatotoxicity in rats by inhibiting inflammatory reactions with the improvement of some serum hepatic transaminases, histopathological picture and immunohistochemical markers.

Cocaine and heroin interact differently with nondrug reinforcers in a choice situation

The present study used a rat choice model to test how cocaine or heroin economically interacted with two different nondrug reinforcers along the substitute-to-complement continuum. In Experiment 1, the nondrug alternative was the negative reinforcer timeout-from-avoidance (TOA)-that is, rats could press a lever to obtain a period of safety from footshock. One group of rats chose between cocaine and TOA and another group chose between heroin and TOA. The relative prices of the reinforcers were manipulated across phases while controlling for potential income effects. When cocaine was the reinforcer, rats reacted to price changes by increasing their allocation of behavior to the more expensive option, thereby maintaining relatively proportional intake of cocaine and TOA reinforcers across prices, suggesting these reinforcers were complements here. In contrast, when heroin became relatively cheap, rats increased allocation of income to heroin and decreased allocation of income to TOA, suggesting that heroin substituted for safety. Additionally, rats were willing to accept more footshocks when heroin was easily available. In Experiment 2, the nondrug alternative was saccharin, a positive reinforcer. Heroin and saccharin were complements, but there was no consistent effect of price changes on the allocation of behavior between cocaine and saccharin. As a model of the processes that could be involved in human drug use, these results show that drug-taking behavior depends on the type of drug, the type of nondrug alternative available, and the prices of both. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A single dose of cocaine raises SV2A density in hippocampus of adolescent rats

OBJECTIVE

Cocaine is a highly addictive psychostimulant that affects synaptic activity with structural and functional adaptations of neurons. The transmembrane synaptic vesicle glycoprotein 2A (SV2A) of pre-synaptic vesicles is commonly used to measure synaptic density, as a novel approach to the detection of synaptic changes. We do not know if a single dose of cocaine suffices to affect pre-synaptic SV2A density, especially during adolescence when synapses undergo intense maturation. Here, we explored potential changes of pre-synaptic SV2A density in target brain areas associated with the cocaine-induced boost of dopaminergic neurotransmission, specifically testing if the effects would last after the return of dopamine levels to baseline.

METHODS

We administered cocaine (20 mg/kg i.p.) or saline to rats in early adolescence, tested their activity levels and removed the brains 1 hour and 7 days after injection. To evaluate immediate and lasting effects, we did autoradiography with [3H]UCB-J, a specific tracer for SV2A, in medial prefrontal cortex, striatum, nucleus accumbens, amygdala, and dorsal and ventral areas of hippocampus. We also measured the striatal binding of [3H]GBR-12935 to test cocaine's occupancy of the dopamine transporter at both times of study.

RESULTS

We found a significant increase of [3H]UCB-J binding in the dorsal and ventral sections of hippocampus 7 days after the cocaine administration compared to saline-injected rats, but no differences 1 hour after the injection. The [3H]GBR-12935 binding remained unchanged at both times.

CONCLUSION

Cocaine provoked lasting changes of hippocampal synaptic SV2A density after a single exposure during adolescence.

Changes in Endogenous Essential Metal Homeostasis in the Liver and Kidneys during a Six-Month Follow-Up Period after Subchronic Cadmium Exposure

Cadmium (Cd) is one of the most dangerous environmental pollutants. Its mechanism of action is multidirectional; among other things, it disrupts the balance of key essential elements. The aim of this study was to assess how cumulative exposure to Cd influences its interaction with selected essential elements (Cu, Zn, Ca, and Mg) in the kidney and liver during long-term observation (90 and 180 days) after subchronic exposure of rats (90 days) to Cd at common environmental (0.09 and 0.9 mg Cd/kg b.w.) and higher (1.8 and 4.5 mg Cd/kg b.w.) doses. Cd and essential elements were analyzed using the F-AAS and GF-AAS techniques. It was shown that the highest bioaccumulation of Cd in the kidney occurred six months after the end of exposure, and importantly, the highest accumulation was found after the lowest Cd dose (i.e., environmental exposure). Organ bioaccumulation of Cd (>21 μgCd/g w.w. in the kidney and >6 μgCd/g w.w. in the liver) was accompanied by changes in the other studied essential elements, particularly Cu in both the kidney and liver and Zn in the liver; these persisted for as long as six months after the end of the exposure. The results suggest that the critical concentration in human kidneys (40 μgCd/g w.w.), currently considered safe, may be too high and should be reviewed, as the observed long-term imbalance of Cu/Zn in the kidneys may lead to renal dysfunction.

Electroacupuncture regulates gut microbiota to reduce depressive-like behavior in rats

Background and objectives

Growing studies show that gut microbiota is closely associated with depression. Acupuncture treatment could regulate the gut microbiota of many diseases. Here, we aim to observe the effect of electroacupuncture (EA) on gut microbiota in rats that showed depressive-like behavior.

Materials and methods

The rats were randomly divided into normal group, chronic unpredictable mild stress model (CUMS) group, CUMS + electroacupuncture (EA) group, and CUMS + sham-electroacupuncture (Sham) group. The CUMS+EA rats were treated with EA stimulation at bilateral Zusanli (ST36) and Tianshu (ST25) acupoints for 2 weeks (0.7 mA, 2/100 Hz, 30 min/day). The rats in the sham EA group were treated with the same conditions without inserting needles and electrical stimulation. Behavioral tests were conducted by forced swimming test (FST), open field test (OFT), and sucrose preference test (SPT) to assess depression-like behavior in rats. The relative abundance of intestinal bacteria in rat feces was detected by 16S rRNA analysis. The expression of calcitonin-gene-related peptide (CGRP), vasoactive intestinal peptide (VIP), somatostatin (SST), and adrenocorticotropic hormone (ACTH) in serum was detected by ELISA kit, and VIP, CGRP, and SST in the colon were detected by qRT-PCR and Western blot.

Results

Chronic unpredictable mild stress model rats exhibited depressive-like behaviors and had differential abundance vs. control rats. CUMS significantly decreased the relative abundance of Bifidobacterium and Streptococcus at the genus level, CGRP in plasma (p < 0.05), and significantly increased the intestine propulsion rate, the mRNA and protein expression of VIP, SST, and mRNA in the colon, and ATCH in plasma (p < 0.05). EA rats with microbial profiles were distinct from CUMS rats. EA markedly reduced the depressive-like behaviors, significantly increased the intestine propulsion rate, the relative abundance of Bacteroidetes, Proteobacteria, and Actinobacteria at the phylum level, Bifidobacterium and Streptococcus at the genus level, and VIP and CGRP in plasma (p < 0.05), and significantly decreased Firmicutes, the ratio of Firmicutes to Bacteroidetes at the phylum level, ACTH and SST in plasma, and SST mRNA in the colon (p < 0.05).

Conclusion

The antidepressant effect of EA at ST36 and ST25 is related to regulating intestinal flora and the neurotransmitter system. Our study suggests that EA contributes to the improvement of depression, and gut microbiota may be one of the mechanisms of EA effect.

Difference in the Mechanism of Iron Overload-Enhanced Acute Hepatotoxicity Induced by Thioacetamide and Carbon Tetrachloride in Rats

Iron overload has been recognized as a risk factor for liver disease; however, little is known about its pathological role in the modification of liver injury. The purpose of this study is to investigate the influence of iron overload on liver injury induced by two hepatotoxicants with different pathogenesis in rats. Rats were fed a control (Cont), 0.8% high-iron (0.8% Fe), or 1% high-iron diet (1% Fe) for 4 weeks and were then administered with saline, thioacetamide (TAA), or carbon tetrachloride (CCl4). Hepatic and systemic iron overload were seen in the 0.8% and 1% Fe groups. Twenty-four hours after administration, hepatocellular necrosis induced by TAA and hepatocellular necrosis, degeneration, and vacuolation induced by CCl4, as well as serum transaminase values, were exacerbated in the 0.8% and 1% Fe groups compared to the Cont group. On the other hand, microvesicular vacuolation induced by CCl4 was decreased in 0.8% and 1% Fe groups. Hepatocellular DNA damage was increased by iron overload in both models, whereas a synergistic effect of oxidative stress by excess iron and hepatotoxicant was only present in the CCl4 model. The data showed that dietary iron overload exacerbates TAA- and CCl4-induced acute liver injury with different mechanisms.

The effect of 6GHz radiofrequency electromagnetic radiation on rat pain perception

This paper presents data on pain perception in rats exposed to 6 GHz radiofrequency electromagnetic radiation (RF-EMR). Rats were divided into two groups: control (n = 10, 4 replicates per test) and RF-EMR exposed group (n = 10, 4 replicates per test). Nociceptive responses of the groups were measured using rodent analgesiometry. Rats were divided into control and RF-EMR exposed groups. Nociceptive responses were measured using rodent analgesiometry. RF-EMR exposed rats had a 15% delay in responding to hot plate thermal stimulation compared to unexposed rats. The delay in responding to radiant heat thermal stimulation was 21%. We determined that RF-EMR promoted the occurrence of pressure pain as statistical significance by + 42% (p < 0.001). We observed that RF-EMR exposure increased nociceptive pain by + 35% by promoting cold plate stimulation (p < 0.05). RF-EMR exposure did not affect thermal preference as statistical significance but did support the formation of pressure pain perception.

Pharmacokinetics of Afatinib after Intravenous and Oral Administrations in Rats Using Validated UPLC MS/MS Assay

Afatinib is designated as the first-line management therapy for patients with advanced non-small cell lung cancer, and metastatic head and neck cancer. LC coupled to MS/MS can be utilised in therapeutic drug monitoring to ensure optimal use of Afatinib with the reduction of its possible adverse reactions. The aim of this investigation was to determine the pharmacokinetics of Afatinib in rats after single IV (2 mg/kg) and oral (8 mg/kg) doses. Therefore, a selective, sensitive and precise UPLC MS/MS assay thru electrospray ionisation basis with positive ionisation approach was established to measure Afatinib concentrations in the rat. The precision and accuracy of the developed assay method in the concentration range of 10-1000 ng/ml show no significant difference among inter- and-intra-day analysis (P > 0.05). Linearity was detected over the studied range with correlation coefficient, r > 0.995 (n = 6/day). The pharmacokinetics of Afatinib in the rat after a single IV dose showed a mean terminal half-life of 4.6 ± 0.97 h, and a mean clearance 480 ± 80 ml/h/kg. After PO administration, a short absorption phase with a mean Tmax of 1.3 ± 0.6 h with the highest concentration of 513.9 ± 281.1 ng/ml, and the lowest concentration detected after 24 h was 18.8 ± 10.7 ng/ml.

Discrepancies between transcutaneous and estimated glomerular filtration rates in rats with chronic kidney disease

Accurate assessment of the glomerular filtration rate (GFR) is crucial for researching kidney disease in rats. Although validation of methods that assess GFR is crucial, large-scale comparisons between different methods are lacking. Both transcutaneous GFR (tGFR) and a newly developed estimated GFR (eGFR) equation by our group provide a low-invasive approach enabling repeated measurements. The tGFR is a single bolus method using FITC-labeled sinistrin to measure GFR based on half-life of the transcutaneous signal, whilst the eGFR is based on urinary sinistrin clearance. Here, we retrospectively compared tGFR, using both 1- and 3- compartment models (tGFR_1c and tGFR_3c, respectively) to the eGFR in a historic cohort of 43 healthy male rats and 84 male rats with various models of chronic kidney disease. The eGFR was on average considerably lower than tGFR-1c and tGFR-3c (mean differences 855 and 216 μL/min, respectively) and only 20 and 47% of measurements were within 30% of each other, respectively. The relative difference between eGFR and tGFR was highest in rats with the lowest GFR. Possible explanations for the divergence are problems inherent to tGFR, such as technical issues with signal measurement, description of the signal kinetics, and translation of half-life to tGFR, which depends on distribution volume. The unknown impact of isoflurane anesthesia used in determining mGFR remains a limiting factor. Thus, our study shows that there is a severe disagreement between GFR measured by tGFR and eGFR, stressing the need for more rigorous validation of the tGFR and possible adjustments to the underlying technique.

Resurgence of ethanol seeking following voluntary abstinence produced by nondrug differential reinforcement of other behavior

Resurgence refers to the relapse of a target behavior following the worsening of a source of alternative reinforcement that was made available during response elimination. Most laboratory analyses of resurgence have used a combination of extinction and alternative reinforcement to reduce target behavior. In contingency-management treatments for alcohol use disorder, however, alcohol use is not placed on extinction. Instead, participants voluntarily abstain from alcohol use to access nondrug alternative reinforcers. Inasmuch, additional laboratory research on resurgence following voluntary abstinence is warranted. The present experiment evaluated resurgence of rats' ethanol seeking following voluntary abstinence produced by differential reinforcement of other behavior (DRO). Lever pressing produced ethanol reinforcers during baseline phases. During DRO phases, lever pressing continued to produce ethanol and food reinforcers were delivered according to resetting DRO schedules. Ethanol and food reinforcers were suspended during resurgence test phases to evaluate resurgence following voluntary abstinence. Lever pressing was elevated during baseline phases and occurred at near-zero rates during DRO phases. During the resurgence test phases, lever pressing increased, despite that it no longer produced ethanol. The procedure introduced here may help researchers better understand the variables that affect voluntary abstinence from ethanol seeking and resurgence following voluntary abstinence.

Preexposure to running attenuates rats' running-based flavour avoidance: Testing associative blocking with a cover cues or context change

Voluntary running in activity wheels by rats leads to a Pavlovian conditioned aversion to the flavour consumed immediately before the running, causing the rats to avoid that flavour. This learning process, known as running-based flavour avoidance learning (FAL), is weakened when the rats have had repeated exposure to the wheels before. According to the associative account, the association between the background context and running established during the preexposure phase blocks the conditioning of the target flavour because the running is highly predictable by the background context from the outset of the FAL phase. Experiments 1 and 2 examined this account by introducing another flavour as a cue signalling wheel access during the preexposure phase. In the framework of the associative account, the introduction of this cue should impede the formation of the context-running association during the preexposure phase, thereby hindering the contextual blocking of aversive conditioning for the target flavour in the FAL phase. This would result in unweakened FAL. Although the results of Experiment 1 align with this prediction, in Experiment 2, when highly distinct flavours were used as the target and second cues, the preexposure effect was not eliminated. This contradicts the predictions of the associative account, indicating that Experiment 1 may have been influenced by stimulus generalisation. In Experiment 3, changing background contexts between the preexposure and FAL phases had no impact on the preexposure effect, contrary to the predictions of the associative account. In general, the associative account was not supported.

Effects of the novel sodium-dependent phosphate cotransporter 2b inhibitor DZ1462 on hyperphosphatemia in chronic kidney disease

BACKGROUND

Serum phosphate levels remain insufficiently controlled in chronic kidney disease (CKD) patients, and novel therapeutic strategies are needed. Blocking intestinal phosphate absorption mediated by sodium-dependent phosphate cotransporter type 2b (NPT2b) holds promise as one such strategy.

METHODS

The in vitro cellular potency of DZ1462 was evaluated using a radioactive Pi uptake assay on stable Chinese hamster ovary (CHO) cell clones transfected with human NPT2b (hNPT2b) or rat NPT2b (rNPT2b). The ability of DZ1462 to inhibit phosphate absorption was studied in vivo in an acute model after oral bolus challenge with 33PO4 and in an adenine-induced chronic hyperphosphatemia rat model. PK and minitox was also evaluated.

RESULTS

The cellular assays with the hNPT2b-CHO and rNPT2b-CHO clones showed that DZ1462 significantly and potently inhibited phosphate uptake. In vivo, in a chronic Pi-fed rat model, DZ1462 effectively inhibited intestinal Pi uptake. In a hyperphosphatemia rat model, DZ1462 significantly inhibited Pi uptake, and DZ1462 in combination with sevelamer had a synergistic effect. The pharmacokinetics (PK) study confirmed that DZ1462 is a gastrointestinal (GI)-restricted compound that can remain in the intestine for a sufficient duration. In addition, DZ1462 also reduced cardiovascular events and ameliorated osteoporosis in a CKD animal model.

CONCLUSIONS

This study revealed that a GI-restricted NPT2b inhibitor DZ1462 potently inhibits NPT2b in vitro and blocks intestinal phosphate uptake in multiple animal models with potential to reduce various cardiovascular events in CKD models. Therefore, DZ1462 may be useful to treat renal disease patients who have shown an unsatisfactory response to phosphate binders.

Effects of age and diet consistency on the expression of myosin heavy-chain isoforms on jaw-closing and jaw-opening muscles in a rat model

BACKGROUND

Skeletal craniofacial morphology can be influenced by changes in masticatory muscle function, which may also change the functional profile of the muscles.

OBJECTIVES

To investigate the effects of age and functional demands on the expression of Myosin Heavy-Chain (MyHC) isoforms in representative jaw-closing and jaw-opening muscles, namely the masseter and digastric muscles respectively.

METHODS

Eighty-four male Wistar rats were divided into four age groups, namely an immature (n = 12; 4-week-old), early adult (n = 24; 16-week-old), adult (n = 24; 26-week-old) and mature adult (n = 24; 38-week-old) group. The three adult groups were divided into two subgroups each based on diet consistency; a control group fed a standard (hard) diet, and an experimental group fed a soft diet. Rats were sacrificed, and masseter and digastric muscles dissected. Real-time quantitative polymerase chain reaction was used to compare the mRNA transcripts of the MyHC isoforms-Myh7 (MyHC-I), Myh2 (MyHC-IIa), Myh4 (MyHC-IIb) and Myh1 (MyHC-IIx)-of deep masseter and digastric muscles.

RESULTS

In the masseter muscle, hypofunction increases Myh1 (26, 38 weeks; p < .0001) but decreases Myh4 (26 weeks; p = .046) and Myh2 (26 weeks; p < .0001) expression in adult rats. In the digastric muscle, hypofunction increases Myh1 expression in the mature adult rats (38 weeks; p < .0001), while Myh2 expression decreases in adult rats (26 weeks; p = .021) as does Myh4 (26 weeks; p = .001). Myh7 expression is increased in the digastric muscle of mature adult rats subjected to hypofunction (38 weeks; p = <.0001), while it is very weakly expressed in the masseter.

CONCLUSION

In jaw-opening and jaw-closing muscles, differences in myosin expression between hard- and soft-diet-fed rats become evident in adulthood, suggesting that long-term alteration of jaw function is associated with changes in the expression of MyHC isoforms and potential fibre remodelling. This may give insight into the role of function on masticatory muscles and the resultant craniofacial morphology.

Effect of chronic intermittent hypoxia on ocular and intraoral mechanical allodynia mediated via the calcitonin gene-related peptide in a rat

STUDY OBJECTIVES

Obstructive sleep apnea, a significant hypoxic condition, may exacerbate several orofacial pain conditions. The study aims to define the involvement of calcitonin gene-related peptide (CGRP) in peripheral and central sensitization and in evoking orofacial mechanical allodynia under chronic intermittent hypoxia (CIH).

METHODS

Male rats were exposed to CIH. Orofacial mechanical allodynia was assessed using the eyeblink test and the two-bottle preference drinking test. The CGRP-immunoreactive neurons in the trigeminal ganglion (TG), CGRP-positive primary afferents projecting to laminae I-II of the trigeminal spinal subnucleus caudalis (Vc), and neural responses in the second-order neurons of the Vc were determined by immunohistochemistry. CGRP receptor antagonist was administrated in the TG.

RESULTS

CIH-induced ocular and intraoral mechanical allodynia. CGRP-immunoreactive neurons and activated satellite glial cells (SGCs) were significantly increased in the TG and the number of cFos-immunoreactive cells in laminae I-II of the Vc were significantly higher in CIH rats compared to normoxic rats. Local administration of the CGRP receptor antagonist in the TG of CIH rats attenuated orofacial mechanical allodynia; the number of CGRP-immunoreactive neurons and activated SGCs in the TG, and the density of CGRP-positive primary afferent terminals and the number of cFos-immunoreactive cells in laminae I-II of the Vc were significantly lower compared to vehicle-administrated CIH rats.

CONCLUSIONS

An increase in CGRP in the TG induced by CIH, as well as orofacial mechanical allodynia and central sensitization of second-order neurons in the Vc, supported the notion that CGRP plays a critical role in CIH-induced orofacial mechanical allodynia.

Evaluating the efficacy of the selective orexin 1 receptor antagonist nivasorexant in an animal model of binge-eating disorder

OBJECTIVE

Test the efficacy of the selective orexin 1 receptor (OX1R) antagonist (SO1RA) nivasorexant in an animal model of binge-eating disorder (BED) and study its dose-response relationship considering free brain concentrations and calculated OX1R occupancy. Compare nivasorexant's profile to that of other, structurally diverse SO1RAs. Gain understanding of potential changes in orexin-A (OXA) neuropeptide and deltaFosB (ΔFosB) protein expression possibly underlying the development of the binge-eating phenotype in the rat model used.

METHOD

Binge-like eating of highly palatable food (HPF) in rats was induced through priming by intermittent, repeated periods of dieting and access to HPF, followed by an additional challenge with acute stress. Effects of nivasorexant were compared to the SO1RAs ACT-335827 and IDOR-1104-2408. OXA expression in neurons and neuronal fibers as well as ΔFosB and OXA-ΔFosB co-expression was studied in relevant brain regions using immuno- or immunofluorescent histochemistry.

RESULTS

All SO1RAs dose-dependently reduced binge-like eating with effect sizes comparable to the positive control topiramate, at unbound drug concentrations selectively blocking brain OX1Rs. Nivasorexant's efficacy was maintained upon chronic dosing and under conditions involving more frequent stress exposure. Priming for binge-like eating or nivasorexant treatment resulted in only minor changes in OXA or ΔFosB expression in few brain areas.

DISCUSSION

Selective OX1R blockade reduced binge-like eating in rats. Neither ΔFosB nor OXA expression proved to be a useful classifier for their binge-eating phenotype. The current results formed the basis for a clinical phase II trial in BED, in which nivasorexant was unfortunately not efficacious compared with placebo.

PUBLIC SIGNIFICANCE

Nivasorexant is a new investigational drug for the treatment of binge-eating disorder (BED). It underwent clinical testing in a phase II proof of concept trial in humans but was not efficacious compared with placebo. The current manuscript investigated the drug's efficacy in reducing binge-like eating behavior of a highly palatable sweet and fat diet in a rat model of BED, which initially laid the foundation for the clinical trial.

Complex Hippocampal Response to Thermal Skin Injury and Protocols with Hyperbaric Oxygen Therapy and Filipendula ulmaria Extract in Rats

The aim of this study was to evaluate the alterations of the hippocampal function that may be related to anxiogenic response to thermal skin injury, including the morpho-functional alterations, and the effects of hyperbaric oxygen (HBO) and Filipendula ulmaria (FU) extract in the treatment of anxiety-like behavior that coincides with thermal skin injury. A rat thermal skin injury experimental model was performed on 2-month-old male Wistar albino rats. The evaluated therapeutic protocols included HBO and/or antioxidant supplementation. HBO was applied for 7 days in the hyperbaric chamber (100% O2, 2.5 ATA, 60 min). Oral administration of FU extract (final concentration of 100 mg/kg b.w.) to achieve antioxidant supplementation was also applied for 7 days. Anxiety level was estimated in the open field and elevated plus-maze test, which was followed by anesthesia, sacrifice, and collection of hippocampal tissue samples. HBO treatment and FU supplementation significantly abolished anxiogenic response to thermal skin injury. This beneficial effect was accompanied by the reduction in hippocampal pro-inflammatory and pro-apoptotic indicators, and enhanced BDNF and GABA-ARα2S gene expression, previously observed in untreated burns. The hippocampal relative gene expression of melatonin receptors and NPY positively responded to the applied protocols, in the same manner as µ and δ opioid receptors, while the opposite response was observed for κ receptors. The results of this study provide some confirmations that adjuvant strategies, such as HBO and antioxidant supplementation, may be simultaneously applied in the treatment of the anxiety-like behavior that coincides with thermal skin injury.

Effects of cerium oxide nanoparticles on adenine-induced chronic kidney disease model rats

AIM

Cerium oxide, particularly in nanoparticle form (nanoceria), has been investigated for biomedical applications as a promising new agent for treating several pathologies. The aim of the present study was to characterize the pharmacologic effects of nanoceria in an animal model of chronic kidney disease.

METHODS

We created the chronic kidney disease animal model by feeding rats a 0.25% adenine diet. Male Wistar rats were divided into five groups: normal diet, 0.25% adenine diet, or adenine diet containing three different doses or durations of nanoceria treatment. Blood was collected weekly from the tail veins of each rat and analyzed for renal function markers. After 5 weeks, various biochemical markers in serum, plasma, and urine were also analyzed.

RESULTS

In the adenine-treated group, body weight was significantly decreased, and the kidneys lost much of their healthy reddish color and became lumpy and white in appearance. In addition, levels of serum creatinine, blood urea nitrogen, and plasma uremic toxins were significantly increased in adenine-treated rats compared with controls. Renal functional and structural damage in adenine diet model rats tended to be ameliorated by nanoceria ingestion. The high-dose cerium-treated group maintained reddish areas in the kidneys, and the increases in biomarker levels of creatinine, blood urea nitrogen, and inorganic phosphorus were markedly reduced, regardless of treatment duration.

CONCLUSIONS

Ingestion of nanoceria may be effective for improving or preventing renal damage caused by adenine. Geriatr Gerontol Int 2024; 24: 88-95.

Citrate-coated silver nanoparticles loaded with agomelatine provide neuronal therapy in acute cerebral ischemia/reperfusion of rats by inhibiting the oxidative stress, endoplasmic reticulum stress, and P2X7 receptor-mediated inflammasome

Cerebral ischemia and reperfusion are related to various situations like injuries after various traumas, oxidative stress, increased calcium ion, capillary hypoperfusion, microvascular hyperpermeability, leukocyte infiltration, and blood-brain barrier disruption. An antidepressant Agomelatine which is a melatonin receptor (MT1/MT2) agonist and serotonin receptor (5-HT2C) antagonist has been reported by studies to have antioxidant and anti-inflammatory effects. In our study, we aimed to detect the effects of citrate-coated silver nanoparticle-loaded agomelatine application on neurodegeneration, endoplasmic reticulum stress, autophagic and apoptotic cell death, inflammation, and P2X7R expression in the cerebral ischemia-reperfusion model to facilitate the passage of blood-brain barrier. Forty two Sprague-Dawley rats in total were divided into six equal groups (n:7) and applications were performed. Acute cerebral injury in the ischemia-reperfusion model was created 2 h after internal carotid artery ligation in rats and then at the 2nd hour of reperfusion citrate-coated silver nanoparticles loaded with Agomelatine were applied. Twenty four hours later, neurologic analysis on animals in experimental groups was performed, animals were decapitated and GSH, GPx, SOD, CAT, MDA, IL-1β, and TNF-α parameters were examined after taking blood and the cerebral tissue samples. As a result, it was determined that ischemia-reperfusion caused endoplasmic reticulum stress in the cerebral tissues and thus caused cellular injury.

Mifepristone decreases nicotine intake in dependent and non-dependent adult rats

BACKGROUND

Addiction to tobacco and nicotine products has adverse health effects and afflicts more than a billion people worldwide. Therefore, there is an urgent need for new treatments to reduce tobacco and nicotine use. Glucocorticoid receptor blockade shows promise as a novel treatment for drug abuse and stress-related disorders.

AIM

These studies aim to investigate whether glucocorticoid receptor blockade with mifepristone diminishes the reinforcing properties of nicotine in rats with intermittent or daily long access to nicotine.

METHODS

The rats self-administered 0.06 mg/kg/inf of nicotine for 6 h per day, with either intermittent or daily access for 4 weeks before treatment with mifepristone. Daily nicotine self-administration models regular smoking, while intermittent nicotine self-administration models occasional smoking. To determine whether the rats were dependent, they were treated with the nicotinic acetylcholine receptor antagonist mecamylamine, and somatic signs were recorded.

RESULTS

The rats with intermittent access to nicotine had a higher level of nicotine intake per session than those with daily access but only the rats with daily access to nicotine showed signs of physical dependence. Furthermore, mecamylamine increased nicotine intake during the first hour of access in rats with daily access but not in those with intermittent access. Mifepristone decreased total nicotine intake in rats with intermittent and daily access to nicotine. Moreover, mifepristone decreased the distance traveled and rearing in the open field test and operant responding for food pellets.

CONCLUSION

These findings indicate that mifepristone decreases nicotine intake but this effect may be partially attributed to the sedative effects of mifepristone.

Rats and their helminth parasites: Potential zoonosis threats of land use change in the northeastern sub-watersheds of Mount Makiling, Laguna, Philippines

The continuous challenges of land use change have brought potential threats to biodiversity and the spread of zoonotic diseases. In this study, synanthropic rodents and their helminth parasites were used as sentinels to assess the potential impact of land use on zoonosis. Rats were collected in different ecosystems, namely agricultural, agroforest, and residential areas in the northeastern sub-watersheds of Mount Makiling, Laguna, Philippines. Three (3) species of rats were captured, namely, Rattus tanezumi, Rattus norvegicus, and Rattus exulans. Of the total 180 rats collected, 92.7 % were found infected with helminth parasites, namely Hymenolepis diminuta, Hymenolepis nana, Taenia pisiformis, and Strobilocercus fasciolaris (cestodes); Angiostrongylus cantonensis, Nippostrongylus brasiliensis, Strongyloides ratti, Capillaria hepatica, Trichuris muris, and Rictularia sp. (nematodes); and Echinostoma ilocanum (trematode). Of these 11 species, nine (9) were considered zoonotic. This study provides important information on the helminth parasites of rats in the northeastern sub-watersheds of Mount Makiling and the potential threat of zoonotic transmission due to increasing land use change and urbanization in the area. Moreover, urbanization can provide favorable eco-epidemiological conditions for rodent-borne pathogens, such as parasites, that are seriously threatening agricultural settings and human settlements in these areas.

A novel animal model of abdominal aortic aneurysm by mechanical injury

The present study established a novel and reproducible animal model to study abdominal aortic aneurysms. In total, 22 adult Lewis rats underwent a procedure to produce mechanical injuries at the infrarenal aorta which was opened temporarily. The aortas were injured 6 times and repaired. Those rats were divided into 2 groups and the aortic aneurysm tissue was harvested after 42 (6-week group) or 63 (9-week group) days and evaluated for the progression of aortic aneurysms. In the 6-week group, changes in the aneurysm were observed in 6/10 (60%) rats and the mean maximum diameter of the aorta demonstrated a 119% increase in size from the baseline measurement. In the 9-week group, changes in the aneurysm were observed in 8/11 (88%) rats and the mean maximum diameter of aorta demonstrated a 133% increase in size. Additional findings from the aortic aneurysm tissue were found microscopically, including the destruction of the tunica media and the elastic fiber. The present study demonstrated that this novel animal model for the development of abdominal aortic aneurysms (AAAs) produced by mechanical injury may have high reproducibility and similar gross and microscopic morphology to humans. This model could be helpful to investigate the treatment of AAAs.

Selective orexin 1 receptor antagonism does not affect effort-based responding for sucrose reward in rats

In rodents, orexin neuropeptides regulate motivation and reward-seeking via orexin 1 receptor (OX1R) signaling in the mesolimbic dopaminergic system. This role is clearly established for rewards inherent to drugs of abuse but less so for natural rewards. Reported effects of the selective OX1R antagonist (SO1RA) SB-334867 on motivation for palatable food are ambiguous. In our experimental conditions neither SB-334867, nor two additional, structurally different SO1RAs, ACT-335827 and the clinical development candidate nivasorexant, affected effort-based responding for sucrose in rats. The positive control lisdexamfetamine, approved for psychiatric disorders associated with altered reward sensitivity such as binge eating disorder, increased effort-based responding.

Short-term dynamic characteristics of diuresis during exogenous pressure perturbations with and without arterial baroreflex control

Although body fluid volume control by the kidneys may be classified as a long-term arterial pressure (AP) control system, it does not necessarily follow that the urine flow (UF) response to changes in AP is slow. We quantified the dynamic characteristics of the UF response to short-term AP changes by changing mean AP between 60 mmHg and 100 mmHg every 10 s according to a binary white noise sequence in anesthetized rats (n = 8 animals). In a baro-on trial (the carotid sinus baroreflex was enabled), the UF response represented the combined synergistic effects of pressure diuresis (PD) and neurally mediated antidiuresis (NMA). In a baro-fix trial (the carotid sinus pressure was fixed at 100 mmHg), the UF response mainly reflected the effect of PD. The UF step response was quantified using the sum of two exponential decay functions. The fast and slow components had time constants of 6.5 ± 3.6 s and 102 ± 85 s (means ± SD), respectively, in the baro-on trial. Although the gain of the fast component did not differ between the two trials (0.49 ± 0.21 vs. 0.66 ± 0.22 µL·min-1·kg-1·mmHg-1), the gain of the slow component was greater in the baro-on than in the baro-fix trial (0.51 ± 0.14 vs. 0.09 ± 0.39 µL·min-1·kg-1·mmHg-1, P = 0.023). The magnitude of NMA relative to PD was calculated to be 32.2 ± 29.8%. In conclusion, NMA contributed to the slow component, and its magnitude was approximately one-third of that of the effect of PD.NEW & NOTEWORTHY We quantified short-term dynamic characteristics of the urine flow (UF) response to arterial pressure (AP) changes using white noise analysis. The UF step response approximated the sum of two exponential decay functions with time constants of ∼6.5 s and 102 s. The neurally mediated antidiuretic (NMA) effect contributed to the slow component of the UF step response, with the magnitude of approximately one-third of that of the pressure diuresis (PD) effect.

Resurgence Following Higher or Lower Quality Alternative Reinforcement

Resurgence is a temporary increase in a previously suppressed target behavior following a worsening in reinforcement conditions. Previous studies have examined how higher rates or magnitudes of alternative reinforcement affect suppression of the target behavior and subsequent resurgence. However, there has been no investigation of the effects of higher versus lower qualities of alternative reinforcement on resurgence. Using a three-phase resurgence preparation with rats, the present experiments examined the effects of an alternative reinforcer that was of higher (Experiment 1) or lower (Experiment 2) quality than the reinforcer that had previously maintained the target behavior. The results of both experiments showed greater reductions in target behavior with a higher quality alternative reinforcer and larger increases in target responding when a higher quality alternative reinforcer was removed. Along with prior findings with higher rates and magnitudes of alternative reinforcement, these findings suggest that variations in reinforcer dimensions that increase the efficacy of alternative reinforcement also tend to increase resurgence when alternative reinforcement is removed. The results are discussed in terms of the resurgence as choice in context model and in terms of potential clinical implications.

Long-lasting developmental effects in rat offspring after maternal exposure to acetamiprid in the drinking water during gestation

Neonicotinoids (NNTs) are a class of insecticides proposed to be safe for pest control in urban, suburban, and agricultural applications. However, little is known about their developmental effects after repeated low-dose exposures during gestation. Here, we tested a dose considered subthreshold for maternal toxicity in rats (6 mg/kg/day) by assessing several morphological, biochemical, and neurobehavioral features in preterm fetuses and developing pups after maternal administration of the NTT acetamiprid (ACP) dissolved in the drinking water during gestational days (GD) 2-19. The exploratory evaluation included monitoring maternal body weight gain, fetal viability, body weight and sex ratio, cephalic length, neonatal body weight and sex ratio, metabolic enzymes in the placenta, maternal blood and fetal liver, and anogenital distance and surface righting response during infancy. We also used the circling training test to study the integrity of the associative-spatial-motor response in adolescence. Results showed no consistent findings indicating maternal, reproductive or developmental toxicity. However, we found ACP effects on maternal body weight gain, placental butyrylcholinesterase activity, and neurobehavioral responses, suggestive of a mild toxic action. Thus, our study showed a trend for developmental susceptibility at a dose so far considered subtoxic. Although the ACP concentration in environmental samples of surface water and groundwater has been mostly reported to be much lower than that used in our study, our results suggest that the ACP point of departure used in current guidelines aimed to prevent developmental effects may need to be verified by complementary sensitive multiple-endpoint testing in the offspring.

Delayed escape behavior requires claustral activity

Animals are known to exhibit innate and learned forms of defensive behaviors, but it is unclear whether animals can escape through methods other than these forms. In this study, we develop the delayed escape task, in which male rats temporarily hold the information required for future escape, and we demonstrate that this task, in which the subject extrapolates from past experience without direct experience of its behavioral outcome, does not fall into either of the two forms of behavior. During the holding period, a subset of neurons in the rostral-to-striatum claustrum (rsCla), only when pooled together, sustain enhanced population activity without ongoing sensory stimuli. Transient inhibition of rsCla neurons during the initial part of the holding period produces prolonged inhibition of the enhanced activity. The transient inhibition also attenuates the delayed escape behavior. Our data suggest that the rsCla activity bridges escape-inducing stimuli to the delayed onset of escape.

Toxicokinetics of MDMA and Its Metabolite MDA in Rats

OBJECTIVES

To investigate the toxicokinetic differences of 3,4-methylenedioxy-N-methylamphetamine (MDMA) and its metabolite 4,5-methylene dioxy amphetamine (MDA) in rats after single and continuous administration of MDMA, providing reference data for the forensic identification of MDMA.

METHODS

A total of 24 rats in the single administration group were randomly divided into 5, 10 and 20 mg/kg experimental groups and the control group, with 6 rats in each group. The experimental group was given intraperitoneal injection of MDMA, and the control group was given intraperitoneal injection of the same volume of normal saline as the experimental group. The amount of 0.5 mL blood was collected from the medial canthus 5 min, 30 min, 1 h, 1.5 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h after administration. In the continuous administration group, 24 rats were randomly divided into the experimental group (18 rats) and the control group (6 rats). The experimental group was given MDMA 7 d by continuous intraperitoneal injection in increments of 5, 7, 9, 11, 13, 15, 17 mg/kg per day, respectively, while the control group was given the same volume of normal saline as the experimental group by intraperitoneal injection. On the eighth day, the experimental rats were randomly divided into 5, 10 and 20 mg/kg dose groups, with 6 rats in each group. MDMA was injected intraperitoneally, and the control group was injected intraperitoneally with the same volume of normal saline as the experimental group. On the eighth day, 0.5 mL of blood was taken from the medial canthus 5 min, 30 min, 1 h, 1.5 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h after administration. Liquid chromatography-triple quadrupole tandem mass spectrometry was used to detect MDMA and MDA levels, and statistical software was employed for data analysis.

RESULTS

In the single-administration group, peak concentrations of MDMA and MDA were reached at 5 min and 1 h after administration, respectively, with the largest detection time limit of 12 h. In the continuous administration group, peak concentrations were reached at 30 min and 1.5 h after administration, respectively, with the largest detection time limit of 10 h. Nonlinear fitting equations for the concentration ratio of MDMA and MDA in plasma and administration time in the single-administration group and continuous administration group were as follows: T=10.362C-1.183, R2=0.974 6; T=7.397 3C-0.694, R2=0.961 5 (T: injection time; C: concentration ratio of MDMA to MDA in plasma).

CONCLUSIONS

The toxicokinetic data of MDMA and its metabolite MDA in rats, obtained through single and continuous administration, including peak concentration, peak time, detection time limit, and the relationship between concentration ratio and administration time, provide a theoretical and data foundation for relevant forensic identification.

N-acetylserotonin alleviates retinal ischemia-reperfusion injury via HMGB1/RAGE/NF-κB pathway in rats

AIM

To observe the effects of N-acetylserotonin (NAS) administration on retinal ischemia-reperfusion (RIR) injury in rats and explore the underlying mechanisms involving the high mobility group box 1 (HMGB1)/receptor for advanced glycation end-products (RAGE)/nuclear factor-kappa B (NF-κB) signaling pathway.

METHODS

A rat model of RIR was developed by increasing the pressure of the anterior chamber of the eye. Eighty male Sprague Dawley were randomly divided into five groups: sham group (n=8), RIR group (n=28), RIR+NAS group (n=28), RIR+FPS-ZM1 group (n=8) and RIR+NAS+ FPS-ZM1 group (n=8). The therapeutic effects of NAS were examined by hematoxylin-eosin (H&E) staining, and retinal ganglion cells (RGCs) counting. The expression of interleukin 1 beta (IL-1β), HMGB1, RAGE, and nod-like receptor 3 (NLRP3) proteins and the phosphorylation of nuclear factor-kappa B (p-NF-κB) were analyzed by immunohistochemistry staining and Western blot analysis. The expression of HMGB1 protein was also detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

H&E staining results showed that NAS significantly reduced retinal edema and increased the number of RGCs in RIR rats. With NAS therapy, the HMGB1 and RAGE expression decreased significantly, and the activation of the NF-κB/NLRP3 pathway was antagonized along with the inhibition of p-NF-κB and NLRP3 protein expression. Additionally, NAS exhibited an anti-inflammatory effect by reducing IL-1β expression. The inhibitory of RAGE binding to HMGB1 by RAGE inhibitor FPS-ZM1 led to a significant decrease of p-NF-κB and NLRP3 expression, so as to the IL-1β expression and retinal edema, accompanied by an increase of RGCs in RIR rats.

CONCLUSION

NAS may exhibit a neuroprotective effect against RIR via the HMGB1/RAGE/NF-κB signaling pathway, which may be a useful therapeutic target for retinal disease.

Comparable Toxicity of Surface-Modified TiO2 Nanoparticles: An In Vivo Experimental Study on Reproductive Toxicity in Rats

Nanoparticles (NPs), a distinct class of particles ranging in size from 1 to 100 nm, are one of the most promising technologies of the 21st century, and titanium dioxide NPs (TiO2 NPs) are among the most widely produced and used NPs globally. The increased application of TiO2 NPs raises concerns regarding their global safety and risks of exposure. Many animal studies have reported the accumulation of TiO2 NPs in female reproductive organs; however, evidence of the resultant toxicity remains ambiguous. Since the surface area and chemical modifications of NPs can significantly change their cytotoxicity, we aimed to compare the toxic effects of pristine TiO2 powder with surface-modified TiO2 powders with salicylic acid (TiO2/SA) and 5-aminosalicylic acid (TiO2/5-ASA) on the ovaries, oviducts, and uterus on the 14th day following acute oral treatment. The results, based on alterations in food and water intake, body mass, organ-to-body mass ratio, hormonal status, histological features of tissues of interest, and antioxidant parameters, suggest that the modification with 5-ASA can mitigate some of the observed toxic effects of TiO2 powder and encourage future investigations to create NPs that can potentially reduce the harmful effects of TiO2 NPs while preserving their positive impacts.

Punicalagin improves inflammation and oxidative stress in rat model of pelvic inflammatory disease

Pelvic inflammatory disease (PID) is one of the major public health concerns accounting for 30% of infertility and 50% of ectopic pregnancy cases due to severe inflammation and fibrosis. Punicalagin® are known to exhibit potent anti-inflammatory activity. The aim of this study was to demonstrate the anti-inflammatory and antioxidant effects of Punicalagin®, against pelvic inflammatory disease in rats. Female Sprague Dawley rats (n = 24) were divided into 6 groups (n = 4) as control, PID, prophylactic (low dose and high dose) and therapeutic group (low dose and high dose). PID model was constructed by implanting the rat cervix with mixed microbe (Escherichia Coli and Staphylococcus Aureus) solution. Prophylactic group was gavaged with 3 mg/kg (low dose) and 6 mg/kg (high dose) Punicalagin® daily starting one day before PID induction and therapeutic group was gavaged with 3 mg/kg (low dose) and 6 mg/kg (high dose) Punicalagin® daily starting 1 day after confirmation of PID model. Rats were sacrificed at the end of experiment and samples from upper genital tract were collected for ELISA, antioxidant assay and histopathological examination. According to results, obvious signs of inflammation and oxidative stress including infiltration of neutrophils and significantly raised levels of cytokines, and oxidative stress markers were observed in PID group when compared to control group. Punicalagin® significantly decreased the levels of IL-1β, catalase and lipid peroxidation in both prophylactic and therapeutic groups when compared to PID group. Punicalagin® also decreased the infiltration of leucocytes in uterus of prophylactic and therapeutic group when compared to PID group, as determined by histological examination. On basis of these results, we concluded that Punicalagin® showed anti-inflammatory and antioxidant potential in rat model of pelvic inflammatory disease and could be used as possible therapeutic agent in treatment of PID.

[Influence of chronic immobilization stress on vitamin status in rats fed different diets]

The influence of a stress factor, widespread in modern conditions, on the vitamin status has not been studied enough. At the same time, the negative stress impact can be aggravated against the background of unhealthy nutrition, which in turn affects the vitamin status of the organism. In this regard, the goal of the research was to evaluate the effect of chronic restrict stress on the vitamin supply in rats fed a diet with adequate and increased content of fat, sugar and cholesterol. Material and methods. The experiment was carried out on 37 growing male Wistar rats (initial body weight of 45±5 g) divided into 4 groups. Animals of the 1st (control) and the 2nd groups received a complete semi-synthetic diet (CSSD) (20% protein, 10% fat, 58% carbohydrates in the form of starch, 384 kcal/100 g) for 92 days. The levels of all vitamins and mineral elements in the rats' diets were adequate for growing rats. Rats of the 3rd and the 4th groups were fed a high-calorie, high-fat high-carbohydrate diet (HFHCD) (20% protein, 28% fat, 2% cholesterol, 18% carbohydrates in the form of starch, 20% sucrose, 511 kcal/100 g). Animals of groups 2 and 4 were subjected to daily 90-minute immobilization. The concentration of vitamins A (retinol and retinol palmitate) and E (α-tocopherol) in the blood serum and liver were determined by high-performance liquid chromatography, vitamins B1 and B2 in the liver and urine, as well as riboflavin in the blood serum and 4-pyridoxic acid (4-PA) in urine were determined by fluorimetric methods. Biochemical parameters of blood serum were determined on a biochemical analyzer; the total content of fat, triglycerides (TG) and cholesterol (CH) was determined in the liver. Results. Replacing CSSD with HFHCD, both under restraint stress and without, was accompanied by an increase in liver weight by 1.8-2.0 fold, in its fat content by 2.6-3.3 fold, cholesterol by 32.6-35.3 fold and TG - by 33.0-57.6 fold (p=<0.001). An increase in alanine aminotransferase (ALT) activity by 1.7-2.0 fold (p=<0.01), in low-density lipoprotein (LDL) cholesterol level by 5.4 fold (p=<0.05) and the atherogenic coefficient by 2.5 fold (p<0.01) as well as a decrease in creatinine and urea level (p=<0.05) in blood serum were revealed. Immobilization was accompanied by a decrease in body weight, liver and liver fat in rats fed both CSSD and HFHCD (p<0.05), but didn't affect the blood serum biochemical parameters, with the exception of an increase in ALT activity. If the activity of alkaline phosphatase (ALP) did not change during immobilization of rats fed the CSSD, then in animals fed the high-calorie diet it decreased by 37.5% (p=<0.05 from the control) under its increase against the background of restrict stress by 78.7% (p=<0.01) compared to the indicator of rats of the 3rd group. Immobilization of rats treated with CSSD was accompanied by an increase in both absolute serum α-tocopherol level and concentration correlated with the level of cholesterol and triglycerides by 26.0-57.5% (p<0.05), with a simultaneous decrease in its content in the liver per 1 g of wet tissue by 22.1% (p=0.041) relative to the indicators of intact animals. Immobilization reduced the level of retinol palmitate in the liver by 2.3 times (p<0.01), but did not affect retinol level in the blood serum. At the same time, indicators of B vitamin status (the content of vitamins B1 and B2 in the liver per 1 g of wet tissue and per organ, blood serum riboflavin level, urinary excretion of riboflavin and 4-PA) did not change, with the exception of thiamine urinary excretion, which reduced compared to the control by 38.8%. In rats fed HFHCD, immobilization had no additional effect on the supply with vitamins A and E. The content of vitamins B1 and B2 in the liver in terms of the whole organ was reduced by 14.0-26.7% relative to the indicator in animals of the 3rd group, not subjected to chronic stress, only due to differences in liver weight in animals of these groups. Conclusion. The data obtained indicate that chronic stress has a negative effect on the vitamin status of the body, worsening the supply with vitamins A, E and B1, and substantiate the feasibility of studying the mechanisms of this effect in order to develop effective vitamin complexes for the treatment and prevention of diseases caused by long-term stress.

Spasmolytic Activity of Gentiana lutea L. Root Extracts on the Rat Ileum: Underlying Mechanisms of Action

The roots of Gentiana lutea L. are utilized in the preparation of various beverages and herbal remedies, serving as a traditional remedy for gastrointestinal ailments. The spasmolytic activity that could substantiate the traditional use of G. lutea root had not been investigated. The main objective goal of the study was to determine the validity of its use as a traditional remedy. The extraction of G. lutea root was performed using a 50% hydroethanolic solvent with three different extraction techniques: ultrasound-assisted extraction (UAE), heat-assisted extraction, and percolation. The spasmolytic activity was tested on isolated rat ileum. The mechanism of action was monitored using the models of spontaneous contractions and acetylcholine-, histamine-, CaCl2-, Bay K8644-, L-NAME-, ODQ-, apamin-, BaCl2-, charybdotoxin-, glibenclamide-, TRAM-34-, and quinine-modified contractions. UAE, having the best bioactivity, was further subjected to a liquid-liquid extraction fractionation. HPLC phytochemical analysis was performed for all tested extracts and fractions. Gentian root extracts were rich in secoiridoids, xanthones, and flavonoids. The UAE has shown better results on spontaneous contractions in comparison to its fractions, leading to the more detailed testing of its spasmolytic mechanism of activity. The extract's activity is primarily mediated through intermediate conductance Ca2+-activated K+ channels, ATP-sensitive K+ channels, voltage-sensitive K+ channels, and mechanisms that activate Ca2+ channels. Overall, the G. lutea root shows great potential in the treatment of spasmodic gastrointestinal ailments.

A Novel Tendon Injury Model, Induced by Collagenase Administration Combined with a Thermo-Responsive Hydrogel in Rats, Reproduces the Pathogenesis of Human Degenerative Tendinopathy

Patellar tendinopathy is a common clinical problem, but its underlying pathophysiology remains poorly understood, primarily due to the absence of a representative experimental model. The most widely used method to generate such a model is collagenase injection, although this method possesses limitations. We developed an optimized rat model of patellar tendinopathy via the ultrasound-guided injection of collagenase mixed with a thermo-responsive Pluronic hydrogel into the patellar tendon of sixty male Wistar rats. All analyses were carried out at 3, 7, 14, 30, and 60 days post-injury. We confirmed that our rat model reproduced the pathophysiology observed in human patients through analyses of ultrasonography, histology, immunofluorescence, and biomechanical parameters. Tendons that were injured by the injection of the collagenase-Pluronic mixture exhibited a significant increase in the cross-sectional area (p < 0.01), a high degree of tissue disorganization and hypercellularity, significantly strong neovascularization (p < 0.01), important changes in the levels of types I and III collagen expression, and the organization and presence of intra-tendinous calcifications. Decreases in the maximum rupture force and stiffness were also observed. These results demonstrate that our model replicates the key features observed in human patellar tendinopathy. Collagenase is evenly distributed, as the Pluronic hydrogel prevents its leakage and thus, damage to surrounding tissues. Therefore, this model is valuable for testing new treatments for patellar tendinopathy.

The impact of phosphodiesterase-5 inhibition or angiotensin-converting enzyme inhibition on right and left ventricular remodeling in heart failure due to chronic volume overload

While phosphodiesterase-5 inhibition (PED5i) may prevent hypertrophy and failure in pressure-overloaded heart in an experimental model, the impact of PDE5i on volume-overload (VO)-induced hypertrophy is unknown. It is also unclear whether the hypertrophied right ventricle (RV) and left ventricle (LV) differ in their responsiveness to long-term PDE5i and if this therapy affects renal function. The goal of this study was to elucidate the effect of PDE5i treatment in VO due to aorto-caval fistula (ACF) and to compare PDE5i treatment with standard heart failure (HF) therapy with angiotensin-converting enzyme inhibitor (ACEi). ACF/sham procedure was performed on male HanSD rats aged 8 weeks. ACF animals were randomized for PDE5i sildenafil, ACEi trandolapril, or placebo treatments. After 20 weeks, RV and LV function (echocardiography, pressure-volume analysis), myocardial gene expression, and renal function were studied. Separate rat cohorts served for survival analysis. ACF led to biventricular eccentric hypertrophy (LV: +68%, RV: +145%), increased stroke work (LV: 3.6-fold, RV: 6.7-fold), and reduced load-independent systolic function (PRSW, LV: -54%, RV: -51%). Both ACF ventricles exhibited upregulation of the genes of myocardial stress and glucose metabolism. ACEi but not PDE5i attenuated pulmonary congestion, LV remodeling, albuminuria, and improved survival (median survival in ACF/ACEi was 41 weeks vs. 35 weeks in ACF/placebo, p = .02). PDE5i increased cyclic guanosine monophosphate levels in the lungs, but not in the RV, LV, or kidney. PDE5i did not improve survival rate and cardiac and renal function in ACF rats, in contrast to ACEi. VO-induced HF is not responsive to PDE5i therapy.

A New Rat Study Suggests There May Be a Biologic Explanation for Higher Fentanyl Mortality in Men Than in Women

Could it be possible that we should give some weight to the contribution of biological differences as contributors to the greater fentanyl mortality in males than in females? Most current explanations for a sex difference are based largely on psychosocial and other non-physiologic contributions. Our recent findings suggest a biological contribution. This could have broad implications for the interpretation and prevention of fentanyl overdose deaths.

Immediate and Long-Term Effects of Tibial Nerve Stimulation on the Sexual Behavior of Female Rats

OBJECTIVES

There are limited treatment options for female sexual dysfunction (FSD). Percutaneous tibial nerve stimulation (PTNS) has shown improvements in FSD symptoms in neuromodulation clinical studies, but the direct effects on sexual function are not understood. This study evaluated the immediate and long-term effects of PTNS on sexual motivation and receptivity in a rat model of menopausal women. Our primary hypothesis was that long-term PTNS would yield greater changes in sexual behavior than short-term stimulation.

MATERIALS AND METHODS

In two experiments, after receiving treatment, we placed ovariectomized female rats in an operant chamber in which the female controls access to a male by nose poking. We used five treatment conditions, which were with or without PTNS and no, partial, or full hormone priming. In experiment 1, we rotated rats through each condition twice with behavioral testing immediately following treatment for ten weeks. In experiment 2, we committed rats to one condition for six weeks and tracked sexual behavior over time. We quantified sexual motivation and sexual receptivity with standard measures.

RESULTS

No primary comparisons were significant in this study. In experiment 1, we observed increased sexual motivation but not receptivity immediately following PTNS with partial hormone priming, as compared with priming without PTNS (linear mixed effect models; initial latency [p = 0.34], inter-interval latency [p = 0.77], nose poke frequency [p = 0.084]; eight rats). In experiment 2, we observed trends of increased sexual receptivity (linear correlation for weekly group means; mounts [p = 0.094 for trendline], intromissions [p = 0.073], lordosis quotient [p = 0.58], percent time spent with a male [p = 0.39], decreased percent time alone [p = 0.024]; four rats per condition), and some sexual motivation metrics (linear correlation for weekly group means; nose pokes per interval [p = 0.050], nose poke frequency [p = 0.039], decreased initial latency [p = 0.11]; four rats per condition) when PTNS was applied long-term with partial hormone priming, as compared with hormone-primed rats without stimulation.

CONCLUSIONS

PTNS combined with hormone priming shows potential for increasing sexual motivation in the short-term and sexual receptivity in the long-term in rats. Further studies are needed to examine variability in rat behavior and to investigate PTNS as a treatment for FSD in menopausal women.

The Level of Sex Hormones and Corticosterone in Female Rats during Modeling of Visceral Obesity, Subsequent Physical Activity, and Normalization of the Diet

The effects of diet-induced visceral obesity and non-drug options of its correction on the level of sex hormones and corticosterone were evaluated in 84 female Wistar rats. During stage I, the rats received either a standard diet (STD) or a high-calorie diet (HCD) for 8 weeks. During stage II, the animals were divided into subgroups depending on obesity correction: without correction (STD control and HCD), transition from HCD to STD (HCD/STD) and/or physical activity (treadmill exercise) for the next 8 weeks (HCD/STD+exercise, STD+exercise, and HCD+exercise). Diet-induced visceral obesity resulted in hyperandrogenization and increased blood corticosterone levels in females. Transition from HCD to STD regardless of physical activity led to normalization of testosterone level and, accordingly, to return to the functional norm of estrogen-androgen balance. The positive effect of moderate physical activity on hormonal status is realized only against the background of a balanced diet or during the transition from HCD to STD.