Nitric oxide-induced apoptosis of human dental pulp cells is mediated by the mitochondria-dependent pathway

Viability and oxidative stress of dental pulp cells after indirect application of chemomechanical agents: An in vitro study

AIM

This study evaluated the transdentinal cytotoxic effects of enzymatic agents (EA) for chemomechanical carious tissue removal on human dental pulp cells.

METHODOLOGY

The groups were based on the performed dentine treatments (n = 8): G1: Positive Control (PC - no treatment); G2: Negative Control (NC - 35% H2 O2 for 2 min); G3: Brix 3000™ (BX) for 30 s; G4: BX for 2 min; G5: Papacarie Duo™ (PD) for 30 s; G6: PD for 2 min. The cells were evaluated for viability (VB; MTT assay) and production of reactive oxygen species (ROS; DCFH-DA assay) and nitric oxide (NO; Griess reagent). A scanning electron microscope provided morphological chemical analyses and energy-dispersive X-ray spectroscopy. The data were submitted to the one-way anova statistical test complemented by Tukey (p < .05).

RESULTS

Cell viability decreased by 21.1% and 58.4% in G5 and G6, respectively. ROS production in G3 and G4 maintained basal levels but increased by 171.2% and 75.1% in G5 and G6, respectively.

CONCLUSIONS

The Brix3000™ enzymatic agent did not cause indirect cytotoxic effects on pulp cells, regardless of the application time. Conversely, Papacarie Duo™ reduced viability and increased ROS production by pulp cells.

Methylenetetrahydrofolate reductase polymorphisms in dental caries-induced pulp inflammation and regeneration of dentine-pulp complex: Future perspectives

Dental caries (DC)-induced pulp infections usually undergo the common endodontic treatment, root canal therapy (RCT). Endodontically treated teeth are devitalized, become brittle and susceptible for re-infection which eventually results in dental loss. These complications arise because the devitalized pulp losses its ability for innate homeostasis, repair and regeneration. Therefore, restoring the vitality, structure and function of the inflamed pulp and compromised dentin have become the focal points in regenerative endodontics. There are very few evidences, so far, that connect methylenetetrahydrofolate reductase single nucleotide polymorphisms (MTHFR-SNPs) and dental disorders. However, the primary consequences of MTHFR-SNPs, in terms of excessive homocysteine and folate deficiency, are well-known contributors to dental diseases. This article identifies the possible mechanisms by which MTHFR-SNP-carriers are susceptible for DC-induced pulp inflammation (PI); and discusses a cell-homing based strategy for in vivo transplantation in an orthotopic model to regenerate the functional dentine-pulp complex which includes dentinogenesis, neurogenesis and vasculogenesis, in the SNP-carriers.

Nitric oxide synthase regulates coelomocytes apoptosis through the NF-κB signaling pathway in the sea cucumber Apostichopus japonicus

Nitric oxide synthase (NOS) was initially discovered to participate in the generation of nitric oxide as a defense mechanism against pathogenic infections. In recent years, it has been found that NOS plays a pivotal role in regulating apoptosis and inflammation in mammals. However, the mechanisms underlying NOS-mediated apoptosis in invertebrates remain largely unclear. In this study, we found that the Apostichopus japonicus NOS (AjNOS) expression levels were upregulated by 2.20-fold and 3.46-fold after being challenged with Vibrio splendidus at concentrations of 107 CFU mL-1 and 108 CFU mL-1 for 12 h compared to the control group, respectively. Under these conditions, the rates of coelomocytes apoptosis were increased from 14.7% to 32.7% and 45.4%, respectively. Treatment with NOS inhibitor (l-NAME) resulted in a reduction of coelomocytes apoptosis rates from 32.6% to 26.5% in V. splendidus (107 CFU mL-1) groups and from 42.3% to 33.3% in V. splendidus (108 CFU mL-1) groups, respectively. NOS has been reported to regulate apoptosis through IκBα phosphorylation. Simultaneously, exposure to V. splendidus in conjunction with l-NAME resulted in down-regulation of AjIκBα phosphorylation levels compared to the group infected solely with V. splendidus. Furthermore, immunofluorescence analysis revealed that treatment with l-NAME or interference of AjNOS using siRNA inhibited translocation of AjNF-κB/p65 (RelA) into the nucleus. Previous studies have shown that NF-κB can down-regulate expression levels of Bcl-2 family members, which is an important pathway for regulating apoptosis. In the present study, treatment with l-NAME was found to promote anti-apoptotic AjBcl-2 mRNA increase to 1.41-fold and protein expression increase to 1.86-fold at 12 h post V. splendidus challenge. However, these effects were suppressed by PMA (an NF-κB activator). Overall, our findings demonstrate that AjNOS regulates coelomocytes apoptosis induced by V. splendidus through activation of the AjNF-κB signaling pathway and down-regulation of AjBcl-2 in A. japonicus.

Synthesis, characterization, biological activity and electrochemistry studies of iron(III) complex with curcumin-oxime ligand

Iron overload is a key target in drug development. This study aimed to investigate the coordination of Fe(III) ions with a curcumin-oxime ligand that may be used in the treatment of iron overload. The synthesis of the curcumin-oxime ligand and curcumin-oxime-Fe(III) complex was successfully made and characterized in its solid-state and solution-state using FT-IR, UV-Vis, elemental analysis, and 1 H-NMR. However, in this study, we investigated the apoptotic effects of the curcumin-oxime Fe (III) complex on SW480. SW480 cells were exposed to 99.2% medium for 48 hours. After 48 hours, the incubation period, cells were harvested by centrifugation and washed in phosphate-buffered saline (PBS) and lysed in radio-immunoprecipitation assay (RIPA) buffer for 20 minutes and supernatants were taken and pellets were discarded. ELISA test was used to examine the expression, and activity of cleaved caspase-3, Bax, and Bcl-2 proteins in SW480 cells. ELISA test results indicated that the activities of apoptotic proteins Bax, caspase 3 and Bcl-2 in human SW480 cell lines significantly increased in 48 hours treatment. Also, the activity of Bcl-2 was observed to decrease significantly. Catalase activities of the complex were investigated. The findings showed that the complex has a catalase activity. The findings suggest that this type of complex may constitute a new and interesting basis for the future search of new and more potent drugs. The SOD activity of the result showed that the complexes possessed a considerable SOD activity with an IC50 value of 7.685 µM. Also, when compared with the control, a complex increased the SOD levels (P < .05). Electrochemistry studies in the literature have shown that the Fe3+ /Fe2+ couple redox process occurs in low potential. This value is within the range of compounds that are expected to show superoxide dismutase activity. The Ipc /Ipa shows that one electron transport takes place in the complex. Our results suggest that curcumin-oxime may represent a new approach in the treatment of iron overload.

Physiopathology of nitric oxide in the oral environment and its biotechnological potential for new oral treatments: a literature review

OBJECTIVES

A narrative review on the NO properties and their relationship with the oral environment describing NO's molecular origin, role, and perspectives regarding oral pathological, physiological, and regenerative processes for future applications and possible use as prevention or treatment in dentistry.

MATERIALS AND METHODS

Pubmed was searched using the word "nitric oxide." Reviews, clinical studies, and experimental studies were eligible for the screening process. Similar search procedures were then performed with the additional search words "conservative dentistry," "orthodontics," "endodontics," "implants," "periodontics," "oral cancer," "pulp revascularization," and "oral surgery." Furthermore, references of included articles were examined to identify further relevant articles.

RESULTS

There is a relationship between NO production and oral diseases such as caries, periodontal diseases, pulp inflammation, apical periodontitis, oral cancer, with implants, and orthodontics. Studies on this relationship and uses of NO, in diagnosis, prevention, and treatment, are being developed. Also, some NO and oral cavity patents have already registered.

CONCLUSIONS

The understanding of how NO can interfere in oral health maintenance or disease processes can contribute to elucidate the disease development and optimize treatment approaches.

CLINICAL RELEVANCE

NO has considerable biotechnological potential and can contribute to improving diagnostics and treating the oral environment. As a biomarker, NO has an important role in the early diagnosis of diseases. Regarding treatments, NO can possibly be used as a regulator of inflammation, anti-biofilm action, replacing antibiotics, inducing apoptosis of cancerous cells, and contributing to the angiogenesis. All these studies are initial considerations regarding the relationship between NO and dentistry.

Nitric Oxide in Dental Pulp Tissue: From Molecular Understanding to Clinical Application in Regenerative Endodontic Procedures

Nitric oxide (NO), which is synthesized by the enzyme NO synthase (NOS), is a versatile endogenous molecule with multiple biological effects on many tissues and organs. In dental pulp tissue, NO has been found to play multifaceted roles in regulating physiological activities, inflammation processes, and tissue repair events, such as cell proliferation, neuronal degeneration, angiogenesis, and odontoblastic differentiation. However, there is a deficiency of detailed discussion on the NO-mediated interactions between inflammation and reparative/regenerative responses in wounded dental pulp tissue, which is a central determinant of ultimate clinical outcomes. Thus, the purpose of this review is to outline the current molecular understanding on the roles of Janus-faced molecule NO in dental pulp physiology, inflammation, and reparative activities. Based on this knowledge, advanced physicochemical techniques designed to manipulate the therapeutic potential of NOS and NO production in endodontic regeneration procedures are further discussed. Impact statement The interaction between inflammation and reparative/regenerative responses is very important for regenerative endodontic procedures, which are biologically based approaches intended to replace damaged tissues. Inside dental pulp tissue, endogenous nitric oxide (NO) is generated mainly by immunocompetent cells and dental pulp cells and mediates not only inflammatory/immune activities but also signaling cascades that regulate tissue repair and reconstruction, indicating its involvement in both tissue destruction and regeneration. Thus, it is feasible that NO acts as one of the indicators and modulators in dental pulp repair or regeneration under physiological and pathological conditions.

Acute Toxoplasma gondii infection alters the number of neurons and the proportion of enteric glial cells in the duodenum in Wistar rats

BACKGROUND

Toxoplasma gondii infection can occur through the ingestion of raw meat that contains tissue cysts or food that contains oocysts. Through the ingestion of oocysts, the parasite crosses the intestinal barrier, where the enteric nervous system is located. The objective was to investigate the kinetics of neuronal and glial responses during acute T. gondii infection.

METHODS

We used 45 Wistar rats that were divided into a control group and infected groups that were evaluated at 6, 12, 24, 48, 72 hours, 7 days, 10 days, and 15 days after infection. The rats received 5000 sporulated oocysts of the parasite orally. To detect neurons and enteric glia cells, the myenteric and submucosal plexuses of the duodenum underwent double-labeling immunohistochemical techniques to evaluate HuC/HuD and S100, HuC/HuD and ChAT, and HuC/HuD and nNOS.

KEY RESULTS

We observed a reduction of the total neuron population in the submucosal plexus 72 hours after infection. Cholinergic neurons decreased in the submucosal plexus 15 days after infection, and nitrergic neurons decreased in the myenteric plexus 72 hours after infection. A decrease in the number of glial cells was observed 7 days after infection in the submucosal plexus, and an increase in the enteric glial cell (EGC)/neuron ratio was found in both plexuses 48 hours after infection.

CONCLUSIONS AND INFERENCES

We found decrease of neurons and increase in the EGC/neuron ratio in both plexuses caused by acute T. gondii infection, with major alterations 72 hours after oral infection. The number of cholinergic neurons decreased in the submucosal plexus, and the number of nitrergic neurons decreased in the myenteric plexus. A decrease in the number of enteric glial cells was observed in the submucosal plexus, and an increase in the enteric glial cell/neuron ratio was observed in both ganglionate plexuses of the duodenum.

Biological Activities and Potential Oral Applications of N-Acetylcysteine: Progress and Prospects

N-Acetylcysteine (NAC), a cysteine prodrug and glutathione (GSH) precursor, has been used for several decades in clinical therapeutic practices as a mucolytic agent and for the treatment of disorders associated with GSH deficiency. Other therapeutic activities of NAC include inhibition of inflammation/NF-κB signaling and expression of proinflammatory cytokines. N-Acetylcysteine is also a nonantibiotic compound possessing antimicrobial property and exerts anticarcinogenic and antimutagenic effects against certain types of cancer. Recently, studies describing potentially important biological and pharmacological activities of NAC have stimulated interests in using NAC-based therapeutics for oral health care. The present review focused on the biological activities of NAC and its potential oral applications. The potential side effects of NAC and formulations for drug delivery were also discussed, with the intent of advancing NAC-associated treatment modalities in oral medicine.

Alterations of mitochondrial antioxidant indexes and apoptosis in duck livers caused by Molybdenum or/and cadmium

Cadmium (Cd) and high Molybdenum (Mo) can lead to adverse reactions on animals, but the co-induced toxicity of Mo and Cd to liver in ducks was not well understood. To investigate the co-induced toxic effects of Mo combined with Cd on mitochondrial oxidative stress and apoptosis in duck livers. 240 healthy 11-day-old ducks were randomly divided into 6 groups (control, LMo group, HMo group, Cd group, LMoCd group and HMoCd group). After being treated for 30, 60, 90 and 120 days, liver mitochondrial antioxidant indexes, ceruloplasmin (CP), metallothionein (MT), Bak-1 and Caspase-3 genes mRNA expression levels, and ultrastructural changes were evaluated. The results showed that total antioxidative capacity (T-AOC), catalase (CAT), superoxide dismutase (SOD) and xanthine oxidase (XOD) activities in experimental groups were decreased, whereas malondialdehyde (MDA) content and nitric oxide synthase (NOS) activity were increased compared with control group, and these changes of co-treated groups were more obvious in the later period of the experiment. The mRNA expression levels of CP, Bak-1 and Caspase-3 were up-regulated in experimental groups compared with control group and showed significant difference between co-treated groups and single treated groups. The mRNA expression level of MT in Cd group was higher than that in co-treated groups. Additionally, ultrastructural changes showed karyopyknosis, mitochondrial swelling, vacuolation and disruption of mitochondrial cristae in co-treated groups. Taken together, it was suggested that dietary Mo and Cd might lead to mitochondrial oxidative stress and apoptosis in duck livers, and it showed a possible synergistic relationship between the two elements.

Sodium Nitroprusside Changed The Metabolism of Mesenchymal Stem Cells to An Anaerobic State while Viability and Proliferation Remained Intact

Objective

We used sodium nitroprusside (SNP), a nitric oxide (NO) releasing molecule, to understand its effect on viability and proliferation of rat bone marrow mesenchymal stem cells (BM-MSCs).

Materials and Methods

This experimental study evaluated the viability and morphology of MSCs in the presence of SNP (100 to 2000 µM) at 1, 5, and 15 hours. We chose the 100, 1000, and 2000 µM concentrations of SNP for one hour exposure for further analyses. Cell proliferation was investigated by the colony forming assay and population doubling number (PDN). Na⁺, K⁺, and Ca²⁺ levels as well as activities of lactate dehydrogenase (LDH), alkaline phosphatase (ALP), aspartate transaminase (AST), and alanine transaminase (ALT) were measured.

Results

The viability of MSCs dose-dependently reduced from 750 µM at one hour and 250 µM at 5 and 15 hours. The 100 µM caused no change in viability, however we observed a reduction in the cytoplasmic area at 5 and 15 hours. This change was not observed at one hour. The one hour treatment with 100 µM of SNP reduced the mean colony numbers but not the diameter when the cells were incubated for 7 and 14 days. In addition, one hour treatment with 100 µM of SNP significantly reduced ALT, AST, and ALP activities whereas the activity of LDH increased when incubated for 24 hours. The same treatment caused an increase in Ca²⁺ and reduction in Na⁺ content. The 1000 and 2000 µM concentrations reduced all the factors except Ca²⁺ and LDH which increased.

Conclusion

The high dose of SNP, even for a short time, was toxic. The low dose was safe with respect to viability and proliferation, especially over a short time. However elevated LDH activity might increase anaerobic metabolism.

Role of sodium nitroprusside in regulating retinal ganglion cell damage through mitochondrial transcription factor A

Accumulating evidence has reported that nitric oxide (NO) can be cytotoxic and induce apoptosis. NO can also be genotoxic and cause DNA damage and mutations. It has been shown that NO damages mitochondrial DNA (mtDNA) to a greater extent than nuclear DNA. Sodium Nitroprusside (SNP), a NO donor, could efficiently promote NO formation. The viability of retinal ganglion cells (RGC) and the mtDNA copy numbers could also be altered by SNP conduction. Mitochondrial transcription factor A (TFAM), an mtDNA transcription factor, plays an essential role in the maintenance of mtDNA and mitochondrial homeostasis. The expression of TFAM was up-regulated by low dose SNP while down-regulated by high dose SNP. TFAM overexpression attenuated the regulatory effect of SNP on RGC viability and mtDNA numbers, while TFAM inhibition even amplified the regulatory effect of SNP. Moreover, the expression of apoptosis-related proteins in the mitochondria, Bcl-2 and Bax, were both altered by SNP treatment. These results suggested that TFAM impacted in SNP regulation of RGC viability and mtDNA numbers through the mitochondria-dependent pathway mediated by Bcl-2 and Bax subfamily.

Oxidative Stress and Cell Apoptosis in Caprine Liver Induced by Molybdenum and Cadmium in Combination

To investigate the effects of co-exposure to molybdenum (Mo) and cadmium (Cd) on oxidative stress and cell apoptosis in caprine livers, 36 Boer goats were randomly divided into four groups with nine goats in each group. Three groups were randomly assigned with one of three oral treatments of CdCl2 (0.5 mg Cd kg(-1)·BW) and [(NH4)6Mo7O24·4H2O] (15 mg Mo kg(-1)·BW, 30 mg Mo kg(-1)·BW, 45 mg Mo kg(-1)·BW), while the control group received deionized water. Liver tissues on days 0, 25, and 50 were subjected to determine antioxidant activity indexes and the messenger RNA (mRNA) expression levels of ceruloplasmin (CP), cysteinyl aspartate-specific proteinase-3 (caspase-3), second mitochondria-derived activator of caspases (Smac), and cytochrome-C (Cyt-C) genes. The results showed that significant reductions were observed in total antioxidant capacity (T-AOC) and total superoxide dismutase (T-SOD) activities (P < 0.05), while activities or contents of malondialdehyde (MDA), nitric oxide (NO), and nitric oxide synthase (NOS) were increased (P < 0.05). The mRNA expression levels of CP, caspase-3, Smac, and Cyt-C genes were upregulated (P < 0.05). In addition, histopathological lesions showed different degrees of vacuolar degeneration and edematous and mitochondrial swelling. The results suggest that co-exposure to Mo and Cd could induce oxidative stress and cell apoptosis possibly associated with mitochondrial intrinsic pathway in goat liver and show possible synergistic effects between the two elements.

Ultrasonication processed Panax ginseng berry extract induces apoptosis through an intrinsic apoptosis pathway in HepG2 cells

Ginseng's major active components, ginsenosides, have been known to show anti-cancer, neuroprotective, and anti-inflammatory activities. Ultrasonication processed Panax ginseng berry extract (UGB) contains various ginsenosides. The components are different from Panax ginseng berry extract (GBE). This study was aimed to investigate the cytotoxic mechanism of UGB in HepG2 cells, human hepatocellular carcinoma cell line. HepG2 cells were treated with UGB (0, 10, 20 μg/ml). Cell growth and cellular apoptosis were evaluated by MTT assay and Annexin V/Pi staining, respectively. Intracellular Reactive oxygen species (ROS) levels were also determined by 2', 7'-dichlorofluorescin diacetate (DCFDA) staining. The expressions of Bax, Bcl-2 and caspase-3, the apoptotic markers, were evaluated by Western Blot. UGB dose-dependently inhibited cell growth and induced apoptotic cell death. Intracellular ROS levels were increased. UGB increased the expression of the cleaved form of caspase-3. Furthermore, UGB induced apoptosis of HepG2 cells through Bax activation and Bcl-2 inhibition. In conclusion, UGB induced apoptosis through an intrinsic pathway in HepG2 cells suggesting that UGB might play a role as a novel substance for anti-cancer effect.

Mitochondrial oxidative stress-induced hepatocyte apoptosis reflects increased molybdenum intake in caprine

Molybdenum (Mo) is an essential trace element for animals and humans. However, the high dietary intake of Mo leads to disease conditions in heavy metal pollution areas. To the best of our knowledge, the effect of high levels of Mo on the apoptosis of hepatocyte in goats has not been investigated. Therefore, the aim of the present in vivo study was to investigate the impact of Mo on mitochondrial oxidative stress and apoptosis genes in the liver using real-time quantitative polymerase chain reaction (RT-qPCR) and transmission electron microscopy, respectively. Thirty-six healthy goats were randomly divided into three groups: two groups treated with ammonium molybdate [(NH4)6·Mo7O24·H2O] at 15 and 45 mg Mo kg(-1) BW, respectively, and a control group without treatment. Liver samples were collected from individual goats at different time intervals. The levels of oxidative stress in the mitochondrial membrane and expression of liver-related apoptosis genes, including Bcl-2, Cyt c, caspase-3, and Smac, were examined. The results demonstrated that the levels of superoxide dismutase (SOD) and catalase (CAT) expression were significantly down-regulated in liver cells, whereas malondialdehyde (MDA), nitric oxide (NO), and total nitric oxide synthase (T-NOS) expression was up-regulated (P < 0.01). The expression of Smac, Cyt c, and caspase-3 was significantly up-regulated, whereas Bcl-2 expression was down-regulated in liver cells (P < 0.01). In addition, histopathological examination revealed varying degrees of vacuolization, irregularity, nuclear fission, and mitochondrial swelling and high-density electrons in the cytoplasm of hepatocytes in groups treated with 15 and 45 mg Mo kg(-1) BW. Thus, these results suggested that high molybdenum induced hepatocyte apoptosis and might involve a mitochondrial pathway.

Cape Gooseberry [Physalis peruviana L.] Calyces Ameliorate TNBS Acid-induced Colitis in Rats

BACKGROUND AND AIMS

Physalis peruviana [cape gooseberry] is highly appreciated for its commercial value. The Colombian ecotype is in great demand in the international market, particularly for the unique morphological characteristics of the calyx, which has extended use as a traditional herbal remedy in Colombia because of its anti-inflammatory properties. In this work, the anti-inflammatory activity of the total ethereal extract of Physalis peruviana calyces was evaluated in preventive and therapeutic protocols in a TNBS acid-induced colitis rat model.

METHODS

Colitis was induced by intrarectal administration of TNBS. An evaluation of macroscopic and histopathological parameters in colonic tissue was performed, along with the determination of myeloperoxidase enzyme activity, cytokine levels and gene expression. Additionally, effects on nitric oxide release by lipopolysaccharide [LPS]-stimulated RAW264.7 macrophages and the scavenging activity of DPPH and ABTS free radicals were determined.

RESULTS

The treatment with the Physalis peruviana extract produced a significant improvement in the colonic tissue at both macroscopic and histological levels. IL-1β and TNF-α production was reduced by the extract in both experimental approaches. The groups treated with Physalis peruviana showed a tendency to MUC2 up-regulation and down-regulation of COX-2, iNOS, NLRP3, IL-1β, IL-6 and IL-10 expression. Nitric oxide release in RAW264.7 macrophages was significantly inhibited.

CONCLUSIONS

The Physalis peruviana extract showed intestinal anti-inflammatory activity in the TNBS-induced colitis model, placing this species' calyx, a natural derivative, as a promising source of metabolites that could be used in treatment for inflammatory bowel disease.

Effects of Local Pancreatic Renin-Angiotensin System on the Microcirculation of Rat with Severe Acute Pancreatitis

Severe acute pancreatitis (SAP) is normally related to multiorgan dysfunction and local complications. Studies have found that local pancreatic renin-angiotensin system (RAS) was significantly upregulated in drug-induced SAP. The present study aimed to investigate the effects of angiotensin II receptors inhibitor valsartan on dual role of RAS in SAP in a rat model and to elucidate the underlying mechanisms. 3.8% sodium taurocholate (1 ml/kg) was injected to the pancreatic capsule in order for pancreatitis induction. Rats in the sham group were injected with normal saline in identical locations. We also investigated the regulation of experimentally induced SAP on local RAS expression in the pancreas through determination of the activities of serum amylase, lipase and myeloperoxidase, histological and biochemical analysis, radioimmunoassay, fluorescence quantitative PCR and Western blot analysis. The results indicated that valsartan could effectively suppress the local RAS to protect against experimental acute pancreatitis through inhibition of microcirculation disturbances and inflammation. The results suggest that pancreatic RAS plays a critical role in the regulation of pancreatic functions and demonstrates application potential as AT1 receptor antagonists. Moreover, other RAS inhibitors could be a new therapeutic target in acute pancreatitis.

Oral dependent-dose toxoplasmic infection model induced by oocysts in rats: Myenteric plexus and jejunal wall changes

Toxoplasmosis is a widely distributed disease caused by the protozoan Toxoplasma gondii that is mainly transmitted orally. Once ingested, the parasite crosses the intestinal barrier to reach the blood and lymph systems to migrate to other regions of the host. The objective of this study was to evaluate the changes in the myenteric plexus and the jejunal wall of Wistar rats caused by oral infection with T. gondii oocysts (ME-49 strain). Inocula of 10, 100, 500 and 5000 oocysts were used. The total population of myenteric neurons and the most metabolically active subpopulation (NADH-diaphorase positive - NADH-dp) exhibited a decrease proportional to the dose of T. gondii. There was also a quantitative increase in the subpopulation of NADPH-diaphorase-positive (NADPH-dp) myenteric neurons, indicating greater expression of the NOS enzyme. Neuronal atrophy was observed, and morphological and morphometric alterations such as jejunal atrophy were found in the infected groups. Hypertrophy of the external muscle with the presence of inflammatory foci was observed in the group infected with 5000 oocysts. The changes observed in the infected groups were proportional to the number of oocysts inoculated.

Paroxetine ameliorates changes in hippocampal energy metabolism in chronic mild stress-exposed rats

The molecular mechanisms underlying stress-induced depression have not been fully outlined. Hence, the current study aimed at testing the link between behavioral changes in chronic mild stress (CMS) model and changes in hippocampal energy metabolism and the role of paroxetine (PAROX) in ameliorating these changes. Male Wistar rats were divided into three groups: vehicle control, CMS-exposed rats, and CMS-exposed rats receiving PAROX (10 mg/kg/day intraperitoneally). Sucrose preference, open-field, and forced swimming tests were carried out. Corticosterone (CORT) was measured in serum, while adenosine triphosphate and its metabolites, cytosolic cytochrome-c (Cyt-c), caspase-3 (Casp-3), as well as nitric oxide metabolites (NOx) were measured in hippocampal tissue homogenates. CMS-exposed rats showed a decrease in sucrose preference as well as body weight compared to control, which was reversed by PAROX. The latter further ameliorated the CMS-induced elevation of CORT in serum (91.71±1.77 ng/mL vs 124.5±4.44 ng/mL, P<0.001) as well as the changes in adenos-ine triphosphate/adenosine diphosphate (3.76±0.02 nmol/mg protein vs 1.07±0.01 nmol/mg protein, P<0.001). Furthermore, PAROX reduced the expression of Cyt-c and Casp-3, as well as restoring NOx levels. This study highlights the role of PAROX in reversing depressive behavior associated with stress-induced apoptosis and changes in hippocampal energy metabolism in the CMS model of depression.

Protective roles of selenium on nitric oxide-mediated apoptosis of immune organs induced by cadmium in chickens

Little is known about the influence of subchronic cadmium exposure on apoptosis in the immune organs of birds and the protective effects on apoptosis by selenium against cadmium. The aim of this study was to investigate the effect of subchronic cadmium exposure on nitric oxide and apoptosis in the immune organs of chicken and the protective roles of selenium against cadmium-induced apoptosis. Two hundred ten 30-day-old chickens were randomly assigned to three groups and were fed a basal diet, cadmium+selenium (as 150 mg of CdCl2 per kg of diet+10 mg of Na2SeO3 per kg of diet ) or cadmium (as 150 mg of CdCl2 per kg of diet) in basic diets for 15, 30, 45, and 60 days. Then, the production of nitric oxide, messenger RNA (mRNA level), and the activity of inducible nitric oxide synthase, ultrastructural changes, TUNEL assay, and flow cytometric analysis of apoptosis and Bcl-2 and p53 mRNA levels in the immune organs were examined. The results showed that cadmium exposure caused ultrastructural damage and increased production of nitric oxide, mRNA level, and activity of inducible nitric oxide synthase, the degree, and the number of apoptotic cells in a time-dependent manner. Cadmium exposure decreased Bcl-2 mRNA level and increased p53 mRNA level in a time-dependent manner. Selenium supplementation during dietary cadmium reduced the production of nitric oxide, the mRNA level, and activity of inducible nitric oxide synthase, ultrastructural damage, and apoptosis in the immune organs of chicken. It indicated that cadmium induced nitric oxide-mediated apoptosis of immune organs, and selenium played protective effects against cadmium-induced apoptosis in the immune organs of chickens.