Aggressive behavior and stress response after oxytocin administration in male Norway rats selected for different attitudes to humans

Oxytocin (OXT) is known to influence on social behaviors, including intermale aggression and hypothalamic-pituitary-adrenal (HPA) axis activity. However, there are no data on the effects of oxytocin on intermale aggression and HPA axis activity in rats selected for elimination and enhancement of aggressiveness towards humans. The aim of this study is to elucidate the role of oxytocin in expression of aggressive behavior and stress response in Norway rats selected for elimination (tame) and enhancement (aggressive) of an aggressive-defensive reaction to humans. Oxytocin was administered to males via nasal applications once or for 5 days (daily). Resident-intruder test showed that in aggressive males, single oxytocin administration caused an increase in the latent period of aggressive interactions and a decrease in the percentage of direct aggression time (not including the time of lateral threat postures) as compared to the control aggressive rats administered with saline. After a 5-day oxytocin administration, aggressive animals demonstrated shorter time of aggressive interactions compared to the control rats. Resident-intruder test revealed no significant changes in behavior of tame rats after single oxytocin administration, while multiple administration caused an increase in aggressive behavior in tame rats. Oxytocin applications caused an elevation of corticosterone level after restriction in aggressive males, but did not affect expression of Crh, Crh1 and Crhr2 genes in hypothalamus in either tame or aggressive rats. The data obtained indicate significant role of oxytocinergic system in the behavior formed in the process of selection by reaction to humans.

The adrenal gland circadian clock exhibits a distinct phase advance in spontaneously hypertensive rats

The circadian clock influences a multitude of cellular and biological processes, including blood pressure control. Spontaneously hypertensive rats (SHR) exhibit aberrant circadian rhythms affecting cardiovascular parameters, and they also have abnormal clock gene expression profiles in several organs. Given the important role of the adrenal gland in orchestrating circadian oscillations, we investigated the adrenal gland circadian clock in SHR and control Wistar-Kyoto rats maintained under a 12-hour light-dark cycle. Adrenal glands, livers, and serum samples were collected every 4 h and mRNA was extracted for analysis of clock gene expression. Serum levels of corticosterone and aldosterone were also analyzed. Overall, the circadian profiles of Bmal1, Per2, Per3, Cry1, RevErba, Revervb, and Dbp gene expression in SHR adrenal glands were phase-advanced relative to controls. The expression profile of StAR (a representative gene under circadian control in the adrenal gland), as well as the circadian rhythms of serum concentrations of corticosteroid and aldosterone were also phase advanced. E4bp4 gene expression was significantly higher during the dark period, yet the expression of its transcriptional activator, Rora, was significantly lower throughout the 24 h period in SHR adrenal glands than in controls. This paradoxical high E4bp4 gene expression was, however, not observed in the liver. In addition, Per1, Per2, Per3, Reverba, and Reverbb mRNA tended to be lower in SHR adrenal glands than in controls. Thus, we conclude that SHR possess an abnormal adrenal circadian clock, which may affect the transcriptional regulation of clock-controlled genes, and steroid hormone secretion by the adrenal gland.

Comparison of clinical and histological characteristics of orthodontic tooth movement into recent and healed extraction sites combined with corticotomy in rats

Objective

This study was performed to investigate the rate of tooth movement and histological characteristics of extraction sockets those were subjected to corticotomy.

Methods

A split-mouth randomized controlled trial experiment was designed. Thirty-two adult, male Wistar rats were divided into 2 groups: healing extraction socket (H) and recent extraction socket (R); these groups were randomly classified into 4 subgroups (0/7/21/60 days). The first maxillary molar was extracted on 1 side and 2 months were allowed for complete bone healing; then, the corresponding molar was extracted on the other side and surgical intervention was performed at the mid-alveolar point of the first maxillary molar. Ten grams of continuous force was applied. The outcomes measured were rate of tooth movement, percentage of periodontal space and histological evaluation. The rate of tooth movement was calculated as the measured distance divided by the duration of molar movement. Histomorphometric evaluations were performed on the second and third maxillary molars. The Wilcoxon signed rank test was used to compare differences between the two groups.

Results

There were no significant differences in the rates of tooth movement between H and R groups at any of the 4 time points. The histological appearance and percentage of periodontal space between the R and H groups also demonstrated no significant differences.

Conclusions

The rates of orthodontic tooth movement into recent and healed socket sites did not differ between the groups. Histological analysis of tooth movement revealed regional acceleration during every time period.

Can the discriminative stimulus effects of nicotine function concurrently as modulatory opponents in operant and pavlovian occasion setting paradigms in rats?

Nicotine promotes interoceptive changes in the nervous system. Such interoceptive stimuli play important roles in modulating addictive behavior. Operant and Pavlovian stimulus control modulate responsiveness to environmental stimuli related to drug-seeking and self-administration. Nicotine functions as a discriminative stimulus in modulating operant behavior as well as Pavlovian feature stimuli in modulating the conditional responding (CR) to exteroceptive CS→US contingencies. Elucidation of the interaction of these interoceptive stimulus control functions is vital for a comprehensive understanding of nicotine use/abuse, which might lead to better behavioral treatment strategies. This experiment evaluated the interaction among Pavlovian feature positive (FP) and feature negative (FN) effects of nicotine on concurrently occurring operant S^D and S^Δ effects. Sixteen rats were trained in a Pavlovian and operant bidirectional contingency paradigm, using nicotine (0.3 mg/kg) and non-drug (saline) states as interoceptive cues for operant discriminative stimulus conditions (S^D and S^Δ) as well as Pavlovian FP and FN for a light-CS, either leading to a shared food pellet outcome or non-outcome. Nicotine and saline sessions were intermixed. For one group of rats (n = 8), nicotine served as an S^D for lever pressing (variable interval 60 s) and simultaneously functioned as an FN for CS-light→noUS relation on the same sessions. On intermixed sessions, saline served as the S^Δ for lever pressing (non-reinforced) and FP, during which the 8-sec light preceded delivery of the food pellet (variable time ITI = 60 s). For the other group (n = 8) nicotine served as the S^Δ (lever pressing non-reinforced) and FP for the CS, with saline serving in the reverse roles. Consecutive brief non-reinforcement tests revealed that: A) rates of lever pressing were significantly greater in S^D than S^Δ with nicotine and saline suggesting strong operant discriminative stimulus control; B) FP responding to the light CS with nicotine and saline was evident; and C) FN suppression of the CR with nicotine was not evident but weak under saline. These data suggest that nicotine can function as an interoceptive context that hierarchically can enter into concurrently opposing modulatory relations in Pavlovian and operant drug discrimination procedures.

Lipid metabolism in adipose tissue and liver from diet-induced obese rats: a comparison between Wistar and Sprague-Dawley strains

Some researchers have proposed important variations in adipose tissue among different strains of rats and mice in response to a high-caloric (hc) diet, but data concerning the mechanisms underlying these differences are scarce. The aim of the present research was to characterize different aspects of triacylglycerol (TG) metabolism and clock genes between Sprague-Dawley and Wistar rats. For this purpose, 16 male Sprague-Dawley and 16 male Wistar rats were divided into four experimental groups (n = 8) and fed either a normal-caloric (nc) diet or a hc diet for 6 weeks. After sacrifice, liver and epididymal, perirenal, mesenteric, and subcutaneous adipose tissue depots were dissected, weighed and immediately frozen. Liver TG content was quantified, RNA extracted for gene expression analysis and fatty acid synthase enzyme activity measured. Two-way ANOVA and Student's t test were used to perform the statistical analyses. Under hc feeding conditions, Wistar rats were more prone to fat accumulation in adipose tissue, especially in the epididymal fat depot, due to their increased lipogenesis and fatty acid uptake. By contrast, both strains of rats showed similarly fatty livers after hc feeding. Peripheral clock machinery seems to be a potential explanatory mechanism for Wistar and Sprague-Dawley strain differences. In conclusion, Wistar strain seems to be the best choice as animal model in dietary-induced obesity studies.

Mutant UBQLN2P497H in motor neurons leads to ALS-like phenotypes and defective autophagy in rats

Mutations in ubiquilin2 (UBQLN2) have been linked to abnormal protein aggregation in amyotrophic lateral sclerosis (ALS). The mechanisms underlying UBQLN2-related neurodegenerative diseases remain unclear. Using a tetracycline-regulated gene expression system, the ALS-linked UBQLN2^P497H mutant was selectively expressed in either the spinal motor neurons or astrocytes in rats. We found that selectively expressing mutant UBQLN2^P497H in the spinal motor neurons caused several core features of ALS, including the progressive degeneration of motor neurons, the denervation atrophy of skeletal muscles, and the abnormal protein accumulation. Furthermore, mutant UBQLN2^P497H accumulation was associated with an age-dependent decrease in several core autophagy-related proteins. ALS-like phenotypes were not observed when mutant UBQLN2^P497H was overexpressed in the astrocytes, however, even though the expression of the mutant UBQLN2^P497H protein was higher in these rats. Our results suggest that selectively expressing mutant UBQLN2^P497H in motor neurons is sufficient to trigger the development of ALS in rats. Our results further indicate that the compromised autophagy-lysosomal pathway plays a critical role in the pathogenesis of UBQLN2-related neurodegenerative diseases.

A novel technique with reduced computed tomography exposure to predict vertebral compression fracture: a finite element study based on rat vertebrae

Vertebral compression fractures are a significant clinical issue with an annual incidence of approximately 750,000 cases in the USA alone. Mechanical properties of vertebrae are successfully evaluated through finite element (FE) models based on vertebrae CT. However, clinical drawbacks associated to radiation transmission encouraged to explore the possibility to use selected or reduced portions of the vertebra. The objective of our study was to develop a new procedure to predict vertebral compression fracture from sub-volumes. We reconstructed rat vertebras from micro-CT of thoracic and lumbar groups. Each vertebra was partitioned into three sub-volumes of different axial thickness. FE simulating compression tests were performed on each model to evaluate their failure load and stiffness. Using a power function, a high correlation was found for stiffness and strength. The sub-volume with three fifths thickness had a failure load of 180.7 ± 19.2 N for thoracic and of 209.5 ± 27.4 N for the lumbar vertebra. These values were not significantly different from the values found for the entire vertebra (p > 0.05). Based on our findings, failure loads and stiffnesses obtained with reduced CT scans can be successfully used to predict full vertebral failure. This sub-region analysis and power relationship suggests that one can limit radiation exposure to patients when bone characterization is needed. Graphical abstract Estimated mechanical properties in relation to the extent of the computed tomography reconstruction.

Consumption of non-digestible oligosaccharides elevates colonic alkaline phosphatase activity by up-regulating the expression of IAP-I, with increased mucins and microbial fermentation in rats fed a high-fat diet

We have recently reported that soluble dietary fibre, glucomannan, increased colonic alkaline phosphatase (ALP) activity and the gene expression without affecting the small-intestinal activity and that colonic ALP was correlated with gut mucins (index of intestinal barrier function). We speculated that dietary fermentable carbohydrates including oligosaccharides commonly elevate colonic ALP and gene expression as well as increase mucin secretion and microbial fermentation. To test this hypothesis, male Sprague-Dawley rats were fed a diet containing 30 % lard with or without 4 % fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), raffinose (RAF) and lactulose (LAC), which are non-digestible oligosaccharides or isomalto-oligosaccharides (IMOS; some digestible oligosaccharides) for 2 weeks. Colon ALP activity, the gene expression and gut luminal variables including mucins, organic acids and microbiota were measured. Colonic ALP was significantly elevated in the FOS, RAF and LAC groups, and a similar trend was observed in the GOS group. Colonic expression of intestinal alkaline phosphatase (IAP -I), an ALP gene, was significantly elevated in the FOS, GOS and RAF groups and tended to be increased in the LAC group. Dietary FOS, GOS, RAF and LAC significantly elevated faecal mucins, caecal n-butyrate and faecal ratio of Bifidobacterium spp. Dietary IMOS had no effect on colonic ALP, mucins, organic acids and microbiota. Colon ALP was correlated with mucins, caecal n-butyrate and faecal Bifidobacterium spp. This study demonstrated that non-digestible and fermentable oligosaccharides commonly elevate colonic ALP activity and the expression of IAP-I, with increasing mucins and microbial fermentation, which might be important for protection of gut epithelial homoeostasis.

Toxicological study of doxorubicin-loaded PLGA nanoparticles for the treatment of glioblastoma

Doxorubicin loaded in poloxamer 188-coated PLGA nanoparticles (Dox-NP + P188) was shown to produce a high antitumor effect against the experimental orthotopic 101.8 glioblastoma in rats upon intravenous administration. The objective of the present study was to evaluate the acute and chronic toxicity of this nanoformulation. The parent drug was used as a reference formulation. Acute toxicity of doxorubicin-loaded nanoparticles in mice and rats was similar to that of free doxorubicin. The chronic toxicity study was conducted in Chinchilla rabbits; the treatment regimen consisted of 30 daily intravenous injections using two dosage levels: 0.22 mg/kg/day and 0.15 mg/kg/day. The study included assessment of the body weight, hematological parameters, blood biochemical parameters, urinalysis, and pathomorphological evaluation of the internal organs. The results of the study demonstrated that the hematological, cardiac, and testicular toxicity of doxorubicin could be reduced by binding the drug to PLGA nanoparticles. Coating of PLGA nanoparticles with poloxamer 188 contributed to the reduction of cardiotoxicity. Functional and morphological abnormalities caused by the nanoparticulate doxorubicin were dose-dependent and reversible. Altogether these results provide evidence that the PLGA-based nanoformulation not only might enable the broadening of the spectrum of doxorubicin activity but also an improvement of its safety profile.

Risk of maritime introduction of plague from Madagascar to Mayotte

Plague is a rodent-borne disease caused by Yersinia pestis. Most human infections are bubonic plague, as a result of being bitten by infected rodent fleas. Madagascar, Democratic Republic of Congo and Peru are the three most affected countries. Plague was introduced into eastern Madagascar in 1898 by boat from India. It is estimated that the risk of introduction of plague from Madagascar to neighboring islands is very high due to the maritime links. We conducted a study of plague reservoirs and vectors in Longoni Port in Mayotte and Mahajanga Port in Madagascar during two seasons to highlight a non-negligible risk of introduction of Y. pestis to Mayotte. The results showed that two main reservoirs of plague in Madagascar Suncus murinus and Rattus rattus and the main flea vector Xenopsylla cheopis exists in and surrounding the port of Longoni. Y. pestis was isolated from Rattus norvegicus captured close to the port of Mahajanga during this study. Plague bacteria circulate within populations of rodent without causing rodent die-off in Mahajanga. The risk of introduction of plague from Madagascar to Mayotte exists due to the regular exchanges. Continuous surveillance of rat, shrew and flea populations is therefore necessary in all the surrounding countries that have regular exchanges with Madagascar to prevent the spread of the plague.

The effect of economy type on demand and preference for cocaine and saccharin in rats

BACKGROUND

Economy type is an important determinant of reinforcer value. This study investigated the effect of open and closed economies on demand and preference for cocaine and saccharin in rats.

METHODS

In the first phase, rats were trained to lever press for cocaine infusions or saccharin. The number of presses required for each reinforcer increased across sessions. Cocaine and saccharin economy type was manipulated over groups by varying post-session availability of these reinforcers. One group of rats had three hours' post-session access to unlimited cocaine (open economy). A second group had three hours' post-session access to unlimited saccharin. A third group had no post-session access to either reinforcer (closed economy). In a second phase, rats in the three conditions could make mutually exclusive choices for cocaine or saccharin.

RESULTS

Post-session access to saccharin caused saccharin demand to become more elastic. Post-session access to cocaine had no effect on demand for cocaine but made demand for saccharin more elastic. Results from the choice phase generally paralleled those from the demand phase, the main finding being that post-session saccharin access caused an increase in cocaine preference.

CONCLUSIONS

These results show that manipulating economy type can affect cocaine and non-drug reinforcers differently. Opening the saccharin economy decreased saccharin's value. Opening the cocaine economy did not decrease cocaine's value, but instead led to a devaluation of saccharin. These results suggest that cocaine choice may be determined not only by the reinforcers immediately available, but also by those reinforcers' broader contexts of availability.

The involvement of NR4A1 and NR4A2 in the regulation of the luteal function in rats

The nuclear receptor 4A (NR4A) members play important roles in cellular proliferation, differentiation and apoptosis. The current study first evaluate the expression of ovarian NR4A1 during different luteal stages in rats. Immature rats aged 28 days were treated with sequential Pregnant mare serum gonadotropin (PMSG) (D -2) / human chorionic gonadotropin (hCG) (D 0) to induce pseudopregnancy. Serum progesterone (P₄) and ovarian expression of NR4A1 were detected by RIA and WB, respectively, at follicle stage (D 0), early (D 2), middle (D 7) and late (D 14 and D 20) luteal stages. To confirm the role of NR4A1 during the luteal regression, rats were treated with prostaglandin F_2α analog (PGF) for 0-8 h on D 7 to detect the expressions of NR4A1 and NR4A2. RIA result showed that serum P₄ reached highest level on D 7 and then declined. WB results showed that there were two types of NR4A1 (NR4A1-L and NR4A1-S) expressed in the ovary. The ovarian NR4A1-L decreased at the late luteal stage (D 20). However, the NR4A1-S increased at the late luteal stage (D 14). After PGF treatment on D 7, the expression of NR4A1-S increased which peaked at 0.5-1 h and then declined; while NR4A1-L expression did not change within 8 h. Real-time PCR results showed that the ovarian NR4A1 mRNA increased within 0.5 h, maintained high at 1 h and then declined. The NR4A2 mRNA expression exhibited a similar pattern to that of NR4A1 mRNA, though its abundance was not as high as NR4A1. IHC results revealed that NR4A1-L was expressed mainly in the cytoplasm of luteal steroidogenic cells, faintly expressed in the follicle theca cells, oocytes and the pericytes; while NR4A2 was primarily localized in the cytoplasm of luteal steroidogenic cells. In conclusion, all these results demonstrate that NR4A2 as well as NR4A1 might be involved in the luteal development and luteolysis in rats.

Experimental Endometriosis: Review of the Literature Through a Century and the Iranian Experience

Although endometriosis is not a newly discovered disease, it has still remained enigmatic. Understanding the pathophysiology of this disease is still one of the challenges of gynecology and reproductive medicine. Therefore, the subject of endometriosis treatment faces many questions to be answered. Even though this is not considered to be a rare disease, testing novel treatments on subjects is definitely contrary to medical ethics. This is where importance of animal studies is emphasized. History of animal studies on endometriosis dates back to the time when the young John Sampson presented his theory of retrograde flow of menstruation to the gynecologic society of his time to explain the mechanism of endometriosis. However, most of the medical society of that time favored metaplasia as the main mechanism over the new theory. In order to prove Sampson's theory, animal models were used to induce endometriosis, and that was the first study of experimental endometriosis. Nowadays, although no one uses animals to evaluate Sampson theory of endometriosis, however, experimental endometriosis is widely used to study many different aspects of the disease from pathogenesis to possible options for treatments. Also, since then, various animals and different techniques have been proposed and so there is a huge body of literature on experimental endometriosis. Contrary to many countries, Iranian medical societies have neglected animal models for endometriosis until recently. This review article aims to go through the prominent articles on the subject and introduce different animals and methods to its readers and have a special look at Iranian literature on experimental endometriosis.

Effect of prednisone treatment for 30 and 90 days on bone metabolism in collagen-induced arthritis (CIA) rats

Glucocorticoids (GCs) are often prescribed to treat rheumatoid arthritis (RA) in the long term, but there is still controversy in the administration of GCs, mainly because of the adverse reactions such as osteoporosis. Numerous studies have demonstrated that osteoporosis could be induced by GCs in normal rats. However, few experiments have focused on whether osteoporosis could be induced or aggravated by GCs in collagen induced arthritis (CIA) rats. We have investigated bone changes in CIA rats treated with prednisone at 4.5 mg/kg/day for 30 and 90 days by bone histomorphometry, bone mineral density (BMD), micro-CT, biomechanical test, and enzyme-linked immunosorbant assay. We found that high bone turnover osteoporosis was shown in CIA rats. Prednisone treatment for 30 and 90 days improved articular structure and decelerated the degeneration of the femur in CIA rats, but did not improve BMD and bone biomechanics. We conclude that osteoporosis was not aggravated in CIA rats treated with prednisone for 30 and 90 days. On the contrary, prednisone treatment for 30 and 90 days could prevent bone loss of the femur in CIA rats. There was a negative effect on bone metabolism in CIA rats treated with prednisone for 90 days.

Comparative analysis of osseointegration in various types of acetabular implant materials

BACKGROUND

There is a lack of comparative data on osseointegration (BIC) of acetabular cup surfaces in hip arthroplasty in both normal bone mineral density and in conditions of osteoporosis.

AIM

To compare osseointegration of acetabular implants with various types of surfaces in an animal model with normal and osteoporotic bone tissue.

MATERIAL AND METHODS

The study was performed on 60 rats. To simulate osteoporosis ovariectomy was performed in 30 animals. Thirty healthy rats served as controls. In standardised defects of the distal metadiaphysis of the femur we implanted: porous tantalum Trabecular Metal (A), Trabecular Titanium (B), Titanium with Gription coating (C), Stiktite (D), and Tritanum (E). Bone apposition (osseointegration) was defined as all areas of direct "bone-to-implant contact" (BIC).

RESULTS

No qualitative morphological differences in the evaluation of BIC around different implant types was seen in normal rats and rats with osteoporosis. Connective tissue areas around implants were larger in rats with osteoporosis. Morphometric studies showed that the highest BIC were seen in implants A and B, both in healthy animals ([72.00 ± 3.48]% and [67.46 ± 1.69]%) and ones with osteoporosis ([59.19 ± 2.10]% and [53.36 ± 2.57]%). BIC was (60.10 ± 2.05)%, (60.26 ± 2.36)%, and (61.78 ± 2.27)% around implants C, D and E in healthy rats, respectively. BIC in osteoporosis was (45.39 ± 2.37)%, (47.81 ± 2.41)% and (42.10 ± 1.44)%, respectively.

CONCLUSION

Our study showed that the evaluated implants have good BIC features. Furthermore, based on histomorthometry and histology, Porous tantalum Trabecular Metal (A) and Trabecular Titanium (B) implants exhibit higher BIC with bone tissue.

Therapeutic Potential of Human Turbinate-Derived Mesenchymal Stem Cells in Experimental Acute Ischemic Stroke

Purpose

Mesenchymal stem cells (MSCs) have demonstrated great promises for the treatment of ischemic stroke. Previously, we identified a new source of MSCs located in the inferior turbinate. We investigated therapeutic potentials of human turbinate- derived mesenchymal stem cells (hTMSCs) in ischemic stroke.

Methods

Ischemic stroke was induced by the intraluminal occlusion of middle cerebral artery (MCAo) for 50 minutes in rats. At one day after MCAo, hTMSCs, adipose tissue-derived MSCs (AdMSCs), or phosphate buffered saline (PBS) were transplanted into the striatum. Functional recovery was assessed by repeating behavioral tests including modified neurologic severity score and corner test. At 14 days after MCAo, brains were stained with hematoxylin and eosin (H&E) for measuring infarct volume. The survival of grafted MSCs was evaluated by immunohistochemistry to human nuclei (hNU). Immunohistochemistry with anti-doublecortin (anti-DCX) was performed to assess hippocampal neurogenesis.

Results

Transplantation of hTMSCs following MCAo showed improvements of neurologic function, which was comparable with that of AdMSCs. H&E staining showed no difference in infarct volume among 3 groups. Regarding the survival of grafted MSCs, the number of hNU-expressing cells was not different between hTMSCs- and AdMSCs-treated groups. Finally, hTMSCs increased the number of subgranular DCX-positive cells compared to PBS-treated controls, without affecting hilar ectopic migration of newborn neurons.

Conclusions

hTMSCs could improve functional recovery following ischemic stroke, of which efficacy was similar to AdMSCs. Although hTMSCs showed comparable infarct size and survival of grafted MSCs, transplantation of hTMSCs could upregulate subgranular neurogenesis with no impact on ectopically migrating newborn neurons.

[Influence of aluminum on microRNA29 and β-site amyloid precursor protein cleaving enzyme 1 in the brain of rats]

Objective: To investigate the influence of aluminum on microRNA29 (miR29) subtypes miR29a, miR29a*, miR29b1, miR29b2, miR29c1, and miR29c2 and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) in the brain of rats. Methods: A total of 40 Sprague-Dawley rats were randomly divided into control group and 15, 30, and 45 μmol/kg groups according to the body weight, with 10 rats in each group. The rats were exposed to aluminum (at a dose of 0.1 ml/100 g body weight) by intraperitoneal injection for 8 weeks. The rats in control group were given 0.9% normal saline, and those in exposure groups were given aluminum-maltolate (equivalent volumesof maltolate and aluminum solution were mixed before exposure) . The cerebral cortex and hippocampus were isolated after exposure ended; Western blotting was used to measure the change in BACE1 expression, and real-time reverse transcription polymerase chain reaction was used to measure the mRNA expression of miR29 subtypes in the cerebral cortex and hippocampus. Results: Compared with the control group, the 45 μmol/kg group had a significant increase in BACE1 expression in the cerebral cortex, and the 30 and 45 μmol/kg groups had significant increases in BACE1 expression in the hippocampus (all P<0.05) . Compared with the control group, the 15, 30, and 45 μmol/kg groups had significant reductions in the mRNA expression of miR29a*, miR29b2, miR29c1, and miR29c2 in the cerebral cortex and hippocampus (all P<0.01) , and the 45 μmol/kg group had significant reductions in the mRNA expression of miR29a and miR29b1 in the cerebral cortex and hippocampus (all P<0.05) . The results of correlation analysis showed that there was no correlation between the mRNA expression of miR29a*, miR29b2, miR29c1, and miR29c2 and BACE1 expression in the cerebral cortex and hippocampus (all P>0.05) , while the mRNA expression of miR29a and miR29b1 was negatively correlated with BACE1 expression (cerebral cortex: r=-0.987 and -0.981, P<0.05; hippocampus: r=-0.992 and -0.991, P<0.05) . Conclusion: Aluminum can reduce the expression of miR29 subtypes and increase BACE1 expression in the brain, and the expression of miR29a and miR29b1 is negatively correlated with BACE1 expression.

[The role of high-mobility group box protein 1 in the signaling pathways of myocardial ischemia-reperfusion injury in rats]

Objective: To investigate the role of high-mobility group box protein 1 (HMGB1) in the signaling pathways of myocardial ischemia-reperfusion injury (MIRI) in rats. Methods: Forty male Sprague-Dawley rats, weighing 200-250 g, were randomly divided into 4 groups (n=10) using a random number table: sham operation group (group sham), MIRI group (group IR-C), anti-HMGB1 antibody group (group IR-H-Ig), contrast antibody control group (group IR-Ig). The rat model of MIRI was established by 30 min occlusion of left anterior descending branch (LAD) of coronary artery followed by 180 min reperfusion. In sham group, no blocking of LAD was adopted after thoracotomy. Anti-HMGB1 antibody and contrast antibody immunoglobulin G (IgG) (2 mg/kg) were injected respectively at 30 min of reperfusion in IR-H-Ig and IR-Ig groups. Blood samples were collected from the femoral vein for determination of interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), HMGB1, creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI) concentrations at 180 min of reperfusion. The rats were then sacrificed after blood samples were taken and the pathological changes of myocardial tissue were observed. The mRNA and protein expressions of HMGB1, toll-like receptor 4(TLR4) and nuclear factor (NF)-κB in myocardial tissues were detected by Western blot and real-time quantitative PCR respectively. Results: Compared with the Sham group, the plasma level of IL-6, TNF-α, HMGB1 increased significantly and HMGB1, TLR4 and NF-κB mRNA and protein levels of myocardial tissues up-regulated in IR-C and IR-Ig groups (all P<0.05). The plasma level of CK-MB and cTnI increased significantly in IR-C, IR-H-Ig, IR-Ig group (all P<0.05). Compared with the IR-C group, the levels of the plasma HMGB1, the cytokines mentioned above, CK-MB and cTnI were significantly decreased, and mRNA and protein expressions of HMGB1, TLR4 and NF-κB of myocardial tissues down-regulated in IR-H-Ig group (all P<0.05). Inflammatory cell infiltration in MIRI groups increased significantly, while it was significantly reduced in IR-H-Ig group. Conclusion: Blocking the combination of HMGB1 and TLR4 can effectively alleviate the tissue damage caused by myocardial ischemia-reperfusion in rats.

Consolidating probiotic with dandelion, coriander and date palm seeds extracts against mercury neurotoxicity and for maintaining normal testosterone levels in male rats

Objective

Heavy metals are major elements polluting our universe. The inhalation, ingestion or even contacting human body with these elements results in huge health problems. The most common pollutant in our surrounding is mercury. Therefore, the present study aimed to elucidating the protective ability of hot water extracts of dandelion (DA), coriander (CO), date palm seeds (DS), probiotic supernatant (PS) and their combined mixture against mercury-induced neurotoxicity and altered testosterone levels in male rats.

Methods

Fifty six male rats were randomly allotted into seven groups (n = 8 rats/group). Group1 (negative control; NC) animals were fed on the basal diet only, group2 (positive controls; PC) animals were fed on the basal diet and given an aqueous solution of mercuric chloride (25 ppm mercuric) in drinking water. Animals of the antioxidant-treated groups (3–7) were fed on the basal diet and given an aqueous solution of mercuric chloride (25 ppm mercuric) in drinking water together with the herbal antioxidant extracts and probiotics (25 ml/rat/day) throughout the experimental period. Where, group3 (Hg/CO) given coriander extract, group4 (Hg/DA) given dandelion extract, group5 (Hg/DS) given date palm seeds extract, group6 (Hg/PS) given probiotic supernatant, and group7 (Hg/Mix) given mixture of equal quantities of probiotic supernatant together with the three herbal extracts. The treatment lasted for 6 weeks, animals were sacrificed and blood samples were collected. Blood testosterone, enzyme activity and histopathological sections were performed.

Results

The obtained data exhibited that mercury intoxication revealed increases of lactic dehydrogenase and decreases of glutathione-s-transferase and testosterone. Light microscopic investigations of the brain cortex and cerebellum were suggestive of multiple foci of inflammation, cellular infiltration, gliosis and degeneration. Moreover, decreased glial fibrillary acidic protein (GFAP)-immunoreactivity and potential astrocyte toxicity both reflected impaired neuro-protective function of astrocytes necessary for maintaining the brain structure and function.

Conclusion

Administration of the herbal extracts and their mixture with probiotics enhance the body defense and contain protective factor against mercury neurotoxicity and for maintaining normal testosterone levels in male rats. Also, treatment restored the normal control levels of biochemical attributes and histological architecture.

Changes in striatal dopamine release and locomotor activity following acute withdrawal from chronic nicotine are mediated by CRF1, but not CRF2, receptors

The aim of the present study was to investigate the participation of corticotropin-releasing factor (CRF) receptors (CRF1 and CRF2) in the alterations of the dorsal and ventral striatal dopamine release and the vertical and horizontal locomotor activity observed in rats following chronic nicotine treatment and consequent acute withdrawal. In this purpose, male Wistar rats were exposed to repeated intraperitoneal (ip) injection with nicotine or saline solution for 7 days. On the 8th day or the 9th day the rats were injected intracerebroventricularly (icv) with selective CRF1 antagonist antalarmin or selective CRF2 antagonist astressin_2B or saline solution. Thirty minutes after the icv injection the changes of the horizontal and vertical locomotor activity were recorded in an in vivo conducta system. Immediately after the behavioral recordings the changes of the dorsal and ventral striatal dopamine release were determined in an in vitro superfusion system. On the 8th day, the horizontal and vertical locomotor activities and the dorsal and ventral striatal dopamine releases increased significantly in nicotine-treated rats, compared to the saline-treated ones. On the 9th day, the horizontal locomotor activity and the dorsal striatal dopamine release increased significantly, whereas the vertical locomotor activity and the ventral striatal dopamine release decreased significantly in nicotine-treated rats, compared to the saline-treated ones. All the changes observed were attenuated significantly by antalarmin, but not astressin_2B. The present study demonstrates that the changes of striatal dopamine release and locomotor activity observed following chronic nicotine treatment and consequent acute withdrawal are mediated by CRF1, but not CRF2, receptor.

[Protective effect and mechanism of tHBQ on acute silica dust exposure in rats]

Objective: To study the protective effects and possible mechanisms of tBHQ in rats exposed to acute silicadust. Methods: Male Wistar rats without specific pathogen SPF were randomly divided into control group、model group and intervention group, 32 rats for each group. Rats in the model group and the intervention group were treated with a single non exposed tracheal dust method to establish the rats exposed to silica model. The intervention group was intervened with 1% tBHQ solution, once a day. Each group 8 rats were sacrificed at 3,14,28,60d, respectively.The contents of IL-1,TNF-α, HYP,TGF-β in the lung tissue of rats were determined by enzyme linked immunosorbent assay(ELISA), the contents of MDA and the GSH-PX activity in lung tissue and serum of rats were determined by colorimetry. Results: Compared with the control group, the contents of IL-1 in the lung tissue of the model group and the intervention group at each time point increased with time, the contents of IL-1 of model group reached the maximum at 60d, the contents of IL-1 in intervention group reached the maximum at 28d(P<0.05), except 3 d. Compared with the control group, the contents of TGF-β and HYP in the lung tissue of the model group and the intervention group at 28 and 60 d increased with time and reached the maximum at 60d(P<0.05). Compared with the model group at each time point, the contents of IL-1, TGF-β, HYP in the intervention group were lower than those in the model group(P<0.05). Compared with the control group, the contents of MDA in lung tissue and serum of rats in model group and intervention group at different time points increased with time(P<0.05). Compared with the control group,the activity of GSH-PX in serum and lung tissue of rats in model group and intervention group decreased with time,there was no significant difference in 3d(P<0.05), compared with the control group, the activity of GSH-PX in the lung and serum tissue of in-tervenetion group was higher than model group except the 3d(P<0.05). Conclusion: The intervention of tBHQ can alleviate oxidative stress in rats exposed to silica dust to some extent, improve the antioxidant capacity of the body, and reduce the contents of IL-1, TNF-α, TGF-β,HYP in lung tissue,it has acertain impediment and inhibition effect on the inflammation and fibrosis caused by acute silica dust exposure.

Pulmonary Aspergillus fumigatus infection in rats affects gastrointestinal homeostasis

Microbiota inhabiting mucosal tissues is involved in maintenance of their immune homeostasis. Growing body of evidence indicate that dysbiosis in gut influence immune responses at distal sites including lungs. There are also reports concerning gut involvement with pulmonary injury/inflammation in settings of respiratory viral and bacterial infections. The impact of infections with other microorganisms on gut homeostasis is not explored. In this study, the rat model of sublethal pulmonary infection with Aspergillus fumigatus was used to investigate the effect of fungal respiratory infection on gut immune-mediated homeostasis. Signs of intestinal damage, intestinal and gut-draining lymphoid tissue cytokine responses and gut bacterial microbiota diversity were examined. Intestinal injury, inflammatory cell infiltration, as well as increased levels of intestinal interferon-γ (IFN-γ) and interleukin-17 (IL-17) (as opposed to unchanged levels of anti-inflammatory cytokine IL-10) during the two-week period depict intestinal inflammation in rats with pulmonary A. fumigatus infection. It could not be ascribed to the fungus as it was not detected in the intestine of infected rats. Increased production of pro-inflammatory cytokines by major gut-draining mesenteric lymph nodes point to these lymphoid organs as places of generation of cytokine-producing cells. No changes in spleen or systemic cytokine responses was observed, showing lack of the effects of pulmonary A. fumigatus infection outside mucosal immune system. Drop of intestinal bacterial microbiota diversity (disappearance of several bacterial bands) was noted early in infection with normalization starting from day seven. From day three, appearance of new bacterial bands (unique to infected individuals, not present in controls) was seen, and some of them are pathogens. Alterations in intestinal bacterial community might have affected intestinal immune tolerance contributing to inflammation. Disruption of gut homeostasis during pulmonary infection might render gastrointestinal tract more susceptible to variety of physiological and pathological stimuli. Data which showed for the first time gut involvement with pulmonary infection with A. fumigatus provide the baseline for future studies of the impact of fungal lung infections to gut homeostasis, particularly in individuals susceptible to these infections.

What makes a landmark effective in adolescent and adult rats? Sex and age differences in a navigation task

In three experiments, rats of different ages were trained in a circular pool to find a hidden platform whose location was defined in terms of a single landmark, a cylinder outside the pool. Following training, two main components of the landmark, its shape and pattern, were tested individually. Experiment 1 was performed by adolescent and adult rats (Exp. 1a, males; Exp. 1b, females). Adult rats always learned faster than the adolescent animals. On test trials, interesting tendencies were found-mainly, one favoring males on the shape test trial, and another favoring females on the pattern test trial. Experiment 2 was conducted only with adolescent rats, and these males and females did not differ when learning the task. However, on test trials the males learned more about the landmark shape component than about the landmark pattern component, while the females learned equally about the two components of the landmark. Finally, Experiment 3 was conducted only with adult rats, and again the males and females did not differ when learning the task. However, on test trials the males learned equally about the two components of the landmark (shape and pattern), but the females learned more about the landmark pattern component than about the landmark shape component. This set of experiments supports the claim that male and female rats can learn rather different things about a landmark that signals the location of the platform, with age being a critical variable.

Acute and repeated dose 26-week oral toxicity study of 20(S)-ginsenoside Rg3 in Kunming mice and Sprague-Dawley rats

Background

20(S)-ginsenoside-Rg3 (C₄₂H₇₂O₁₃), a natural triterpenoid saponin, is extracted from red ginseng. The increasing use of 20(S)-ginsenoside Rg3 has raised product safety concerns.

Methods

In acute toxicity, 20(S)-ginsenoside Rg3 was singly and orally administrated to Kunming mice and Sprague–Dawley (SD) rats at the maximum doses of 1600 mg/kg and 800 mg/kg, respectively. In the 26-week toxicity study, we used repeated oral administration of 20(S)-ginsenoside Rg3 in SD rats over 26 weeks at doses of 0, 20, 60, or 180 mg/kg. Moreover, a 4-week recovery period was scheduled to observe the persistence, delayed occurrence, and reversibility of toxic effects.

Results

The result of acute toxicity shows that oral administration of 20(S)-ginsenoside Rg3 to mice and rats did not induce mortality or toxicity up to 1600 and 800 mg/kg, respectively. During a 26-week administration period and a 4-week withdrawal period (recovery period), there were no significant differences in clinical signs, body weight, food consumption, urinalysis parameters, biochemical and hematological values, or histopathological findings.

Conclusion

The mean oral lethal dose (LD₅₀) of 20(S)-ginsenoside Rg3, in acute toxicity, is above 1600 mg/kg and 800 mg/kg in mice and rats, respectively. In a repeated-dose 26-week oral toxicity study, the no-observed-adverse-effect level for female and male SD rats was 180 mg/kg.

Sumatriptan inhibits the electrophysiological activity of ASICs in rat trigeminal ganglion neurons

Sumatriptan, a selective serotonin 5-HT1 receptor agonist, is an effective therapeutic for migraine attacks. However, the molecular mechanisms underlying sumatriptan migraine relief are still not fully understood. Here, we found that acid-sensing ion channels (ASICs), pH sensors, are peripheral targets of sumatriptan against migraine. Sumatriptan can inhibit the electrophysiological activity of ASICs in the trigeminal ganglion (TG) neurons. In the present study, sumatriptan decreased proton-gated currents mediated by ASICs in a concentration-dependent manner. In addition, sumatriptan shifted concentration-response curves for protons downwards, with a decrease of 37.3 ± 4.6% in the maximum current response but with no significant change in the pH_0.5 value. Sumatriptan inhibition of ASIC currents was blocked by 5-HT_1D receptor antagonist BRL 15572, but not by 5-HT_1B antagonist SB 224289. Moreover, the sumatriptan inhibition of ASICs can be mimicked by the 5-HT_1D receptor agonist L-694,247, but not by the 5-HT_1B agonist CP-93129. Sumatriptan inhibition of ASIC currents was also reversed by G-protein αi subunit inhibitor PTX and 8-Br-cAMP, suggesting the inhibition may involve the intracellular signal transduction. Finally, sumatriptan decreased the number of action potentials induced by acid stimuli in rat TG neurons. Our results indicated that the anti-migraine drug, sumatriptan, inhibited ASICs in rat TG neurons via 5-HT_1D receptor subtype and a cAMP-dependent signal pathway. These observations add to the understanding of the mechanisms that underlie the clinical effectiveness of anti-migraine sumatriptan.