Subchronic exposure to fenpyroximate causes multiorgan toxicity in Wistar rats by disrupting lipid profile, inducing oxidative stress and DNA damage.

BACKGROUND: Fenpyroximate (FEN) is an acaricide that inhibits the complex I of the mitochondrial respiratory chain in mites. Data concerning mammalian toxicity of this acaricide are limited; thus the aim of this work was to explore FEN toxicity on Wistar rats, particularly on cardiac, pulmonary, and splenic tissues and in bone marrow cells. METHODS: rats were treated orally with FEN at 1, 2, 4, and 8 mg/Kg bw for 28 days. After treatment, we analyzed lipid profile, oxidative stress and DNA damage in rat tissues. RESULTS: FEN exposure increased creatinine phosphokinase (CPK) and lactate dehydrogenase (LDH) activities, elevated total cholesterol (T-CHOL), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) concentrations, while decreasing high-density lipoprotein cholesterol (HDL-C). It inhibited acetylcholinesterase (AChE) activity, enhanced lipid peroxidation, protein oxidation, and modulated antioxidant enzymes activities (superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase). Comet assay indicated that FEN induced a dose-dependent DNA damage, contrasting with the micronucleus test showing no micronuclei formation. Nonetheless, FEN exhibited cytotoxicity to bone marrow cells, as evidenced by a reduction in the number of immature erythrocytes among total cells. CONCLUSION: FEN appears to carry out its genotoxic and cytotoxic activities most likely through an indirect pathway that involves oxidative stress.

Maternal diet supplemented with African walnuts enhances cortico-hippocampal gene expression and histomorphology in rat offspring.

BACKGROUND: The brain is built up during pregnancy. How it functions afterwards depends on how the expectant mother's diet nourishes it. Walnuts contain significant quantities of polyunsaturated fatty acids (PUFAs) and bioactive phytochemicals, which enhance brain health and function even with advancing age. This study examined the effects of a walnut-enriched diet (WED) on corticohippocampal histoarchitecture and gene expression in rat offspring. MATERIALS AND METHODS: Twenty-eight female adult Wistar rats (n= 7) averaging about 185 g in weight were used for this study. After mating, pregnant dams were split randomly into four groups: A (standard rat chow/control), B (WED from GD 0 - PND 21), C (WED from GD 0 - PND 1), D (WED from PND 1 - PND 21). Offspring of dams were sacrificed at adolescence (PND 35), with brain tissues of interest harvested for subsequent analyses. RESULTS: We observed no significant correlates in litter size, body, and brain weights across the experimental groups. Histomorphology revealed no distortion in cellular layering and delineation of cells in the PFC and dentate gyrus of both control and WED groups. Nissl staining intensity was enhanced in the offspring of dams exposed to WED versus the control, indicating improved proteostasis. Upregulated mRNA expression of DNMT3a, H2Ax, OPA1, and BDNF was observed in cortical and hippocampal tissues of WEDexposed offspring compared with the control group. CONCLUSION: A diet enriched with African walnuts during early development induced changes predictive of cognitive improvements and enhanced stress-response signalling, plasticity, and neural resilience in rat offspring.

SEW2871 reduces seizures via the sphingosine 1-phosphate receptor-1 pathway in the pentylenetetrazol and phenobarbitone kindling model of drug-refractory epilepsy.

Epilepsy is a prevalent neurological disorder characterized by neuronal hypersynchronous discharge in the brain, leading to central nervous system (CNS) dysfunction. Despite the availability of anti-epileptic drugs (AEDs), resistance to AEDs is the greatest challenge in treating epilepsy. The role of sphingosine-1-phosphate-receptor 1 (S1PR1) in drug-resistant epilepsy is unexplored. This study investigated the effects of SEW2871, a potent S1PR1 agonist, on a phenobarbitone (PHB)-resistant pentylenetetrazol (PTZ)-kindled Wistar rat model. We measured the messenger ribonucleic acid (mRNA) expression of multi-drug resistance 1 (MDR1) and multi-drug resistance protein 5 (MRP5) as indicators for drug resistance. Rats received PHB + PTZ for 62 days to develop a drug-resistant epilepsy model. From day 48, SEW2871 (0.25, 0.5, 0.75 mg/kg, intraperitoneally [i.p.]) was administered for 14 days. Seizure scoring, behaviour, oxidative markers like reduced glutathione, catalase, superoxide dismutase, inflammatory markers like interleukin 1 beta tumour necrosis factor alpha, interferon gamma and mRNA expression (MDR1 and MRP5) were assessed, and histopathological assessments were conducted. SEW2871 demonstrated dose-dependent improvements in seizure scoring and neurobehavioral parameters with a reduction in oxidative and inflammation-induced neuronal damage. The S1PR1 agonist also downregulated MDR1 and MRP5 gene expression and significantly decreased the number of dark-stained pyknotic nuclei and increased cell density with neuronal rearrangement in the rat brain hippocampus. These findings suggest that SEW2871 might ameliorate epileptic symptoms by modulating drug resistance through downregulation of MDR1 and MRP5 gene expression.

Bacillus subtilis ZB423: 90-Day repeat dose oral (gavage) toxicity study in Wistar rats.

The novel genetically modified probiotic Bacillus subtilis ZB423 was assessed in a 90-day repeated-dose oral toxicity study adhering to Good Laboratory Practice (GLP) and Organization for Economic Cooperation and Development (OECD) guidelines. Spray-dried spores at a concentration of 1.1E12 CFU/g were administered at doses of 130, 260, and 519 mg/kg body weight/day correlating to 1.43 × 1011, 2.86 × 1011, and 5.71 × 1011 CFU/kg/day, respectively, by oral gavage to Wistar rats for a period of 90 consecutive days. Results showed no toxicologically relevant findings for B. subtilis ZB423 from measured parameters. The no observed adverse effect level (NOAEL) of B. subtilis ZB423 is 519 mg/kg body weight/day corresponding to 5.71 × 1011 CFU/kg/day for lyophilized B. subtilis ZB423 spores under the test conditions employed.

Unraveling the RAGE-NF-κB pathway: implications for modulating inflammation in diabetic neuropathy through photobiomodulation therapy.

Diabetic peripheral neuropathy (DPN) is a primary complication observed in diabetes that severely affects quality of life. Recent evidence suggests that photobiomodulation (PBM) is a promising therapy against painful conditions and nerve damage. However, the effects of PBM on DPN remains mostly unknown. In the present study, we investigated the efficacy of PBM therapy in modulating proinflammatory cytokine expression in both central and peripheral nervous systems of rats with Streptozotocin (STZ)-induced type 1 diabetes. Male Wistar rats were allocated into control (naïve), diabetic (STZ), and treatment (STZ + PBM) groups. A single intraperitoneal (i.p.) injection of STZ (85 mg/kg) was administered for the induction of diabetes. Animals were subjected to 10 treatment sessions, every other day. The results herein presented indicate that PBM treatment diminishes Receptor for Advanced Glycation End-products (RAGE) and Nuclear Factor Kappa B (NF-Ï°B) expression in peripheral nervous system and suppresses TNF-α expression in central nervous system tissues. Furthermore, PBM-therapy in diabetic rats also induces increased levels of the anti-inflammatory protein IL-10 in both peripheral and central nervous system. Collectively, our findings demonstrate compelling evidence that PBM-therapy modulates cytokine dynamics and influences RAGE/NF-Ï°B axis in a STZ-induced model of type 1 diabetes.

Safety Assessment of a Novel Intravenous Diclofenac Sodium Formulation Following 28-Day Repeated Administration in Wistar Rats.

These toxicity studies aimed to assess the safety and tolerability of a novel intravenous diclofenac sodium (37.5 mg/mL) formulation containing povidone K12 (80 mg/mL) as the key excipient in Wistar rats. This formulation was tested at doses of 3, 7, and 15 mg/kg/day and was administered daily for 28 days by intravenous route. Toxicokinetic estimation revealed a dose-proportional increase in plasma exposure to diclofenac. The formulation was well tolerated in males; however, mortality was observed in females (2/15) at the highest dose (15 mg/kg/day). Adverse gastrointestinal events related to NSAIDS and a few other treatment-related effects on clinical and anatomic pathology were noted at the 15 mg/kg/day dose, which normalized at the end of the 2-week recovery period. In addition, the excipient povidone K12 was present in a higher amount than the approved Inactive Ingredient Database (IID) limit in the proposed novel formulation. It was qualified through a separate 28-day repeated dose toxicity study by intravenous route in Wistar rats. Povidone K12 was found to be well tolerated and safe up to a dose of 165 mg/kg/day. No treatment-related adverse effects were observed in this study. In conclusion, repeated administration of a novel intravenous formulation containing diclofenac sodium was found to be safe up to the dose of 7 mg/kg/day in female rats and 15 mg/kg/day in male rats.

Integrated miRNA-mRNA Analysis Reveals Critical miRNAs and Targets in Diet-Induced Obesity-Related Glomerulopathy.

This study aimed to investigate obesity-related glomerulopathy (ORG) at cellular, structural, and transcriptomic levels. Thirty Wistar rats were randomized into two groups: 15 rats were fed with a standard diet (SD-rats), and 15 rats were fed with a high-fat diet (HFD-rats). After 10 weeks, the weight, kidney function, histological features, and transcriptomic changes were assessed. HFD-rats gained significantly more weight (55.8% vs. 29.2%; p < 0.001) and albuminuria (10,384.04 ng/mL vs. 5845.45 ng/mL; p < 0.001) compared to SD-rats. HFD-rats exhibited early stages of ORG, with predominant mesangial matrix increase and podocyte hypertrophy (PH). These lesions correlated with differentially expressed (DE) genes and miRNAs. Functional analysis showed that miR-205, which was DE in both the kidneys and urine of HFD-rats, negatively regulated the PTEN gene, promoting lipid endocytosis in podocytes. The downregulation of PTEN was proved through a higher PTEN/nephrin ratio in the SD-rats and the presence of lipid vacuoles in HFD-podocytes. This study has found a specific targetome of miRNAs and gene expression in early stages of ORG. Also, it emphasizes the potential value of miR-205 as a urinary biomarker for detecting podocyte injury in ORG, offering a tool for early diagnosis, and opening new avenues for future therapeutic research of obesity-related glomerulopathy.

Comparative Screening of the Liver Gene Expression Profiles from Type 1 and Type 2 Diabetes Rat Models.

Experimental animal models of diabetes can be useful for identifying novel targets related to disease, for understanding its physiopathology, and for evaluating emerging antidiabetic treatments. This study aimed to characterize two rat diabetes models: HFD + STZ, a high-fat diet (60% fat) combined with streptozotocin administration (STZ, 35 mg/kg BW), and a model with a single STZ dose (65 mg/kg BW) in comparison with healthy rats. HFD + STZ- induced animals demonstrated a stable hyperglycemia range (350-450 mg/dL), whereas in the STZ-induced rats, we found glucose concentration values with a greater dispersion, ranging from 270 to 510 mg/dL. Moreover, in the HFD + STZ group, the AUC value of the insulin tolerance test (ITT) was found to be remarkably augmented by 6.2-fold higher than in healthy animals (33,687.0 ± 1705.7 mg/dL/min vs. 5469.0 ± 267.6, respectively), indicating insulin resistance (IR). In contrast, a more moderate AUC value was observed in the STZ group (19,059.0 ± 3037.4 mg/dL/min) resulting in a value 2.5-fold higher than the average exhibited by the control group. After microarray experiments on liver tissue from all animals, we analyzed genes exhibiting a fold change value in gene expression <-2 or >2 (p-value <0.05). We found 27,686 differentially expressed genes (DEG), identified the top 10 DEGs and detected 849 coding genes that exhibited opposite expression patterns between both diabetes models (491 upregulated genes in the STZ model and 358 upregulated genes in HFD + STZ animals). Finally, we performed an enrichment analysis of the 849 selected genes. Whereas in the STZ model we found cellular pathways related to lipid biosynthesis and metabolism, in the HFD + STZ model we identified pathways related to immunometabolism. Some phenotypic differences observed in the models could be explained by transcriptomic results; however, further studies are needed to corroborate these findings. Our data confirm that the STZ and the HFD + STZ models are reliable experimental models for human T1D and T2D, respectively. These results also provide insight into alterations in the expression of specific liver genes and could be utilized in future studies focusing on diabetes complications associated with impaired liver function.

Rosavin thwarts amyloid-ß-induced macromolecular damages and neurotoxicity, exhibiting anti-Alzheimer's disease activity in Wister rat model.

Lately, interest surrounding the utilization of plant-derived compounds as a viable beneficial approach for treating Alzheimer's disease (AD) has significantly increased. This study aimed to assess the defensive properties of rosavin against Alzheimer's disease induced by amyloid-ß, utilizing experimental models. We found that rosavin exhibited anti-aggregation and disaggregation properties, suggesting its potential to prevent the gathering of Aß-aggregates. In vitro experiments revealed that rosavin effectively mitigated the neurotoxicity induced by Aß in Neuro-2a cells, showcasing its protective potential. Rosavin significantly improved the Aß-induced cognitive deficits in Wistar rats, particularly in spatial memory. Which the pathophysiology of AD includes oxidative damage, which negatively impacts biological macromolecules. Triggers the apoptotic process, causing macromolecular destruction. Interestingly, rosavin attenuated Aß-induced macromolecular damages, thereby preserving neuronal integrity. Furthermore, the activation of antioxidative defense enzymes by rosavin inhibited oxidative damage. The positive outcomes associated with rosavin were primarily attributed to its capacity to enhance acetylcholine-mediated effects. Finally, rosavin has the potential to alleviate Aß-induced neurotoxicity and macromolecular damages, ultimately resulting in enhanced memorial and reasoning function in Wistar rats, offering promising prospects for the treatment of AD.

Ultrasound-guided sciatic nerve block in Wistar rat cadavers: Relevant anatomy and injection distribution.

OBJECTIVE: To investigate the feasibility of an ultrasound-guided sciatic nerve block by describing the sonoanatomy and comparing the distribution of two volumes of bupivacaine dye solution for nerve staining. STUDY DESIGN: Randomized, experimental, assessor-blinded cadaveric study. ANIMALS: A total of 40 adult female Wistar rat cadavers. METHODS: After studying the sonoanatomy of the sciatic nerve and adjacent structures using a high-resolution linear transducer (19-5 MHz), rat cadavers were randomly divided into two groups that were administered either 0.1 mL (group 0.1) or 0.2 mL (group 0.2) of bupivacaine dye solution per nerve, delivered via an in-plane technique. The extent of nerve staining was subsequently evaluated following dissection. Statistical analysis consisted of assessing data distribution using the Shapiro-Wilk test, followed by paired t-tests for continuous data, Mann-Whitney U test and McNemar's test for categorical data. Statistical significance was defined as p < 0.05. RESULTS: The sciatic nerve was identified bilaterally as a double ellipsoid-shaped image, surrounded by a hyperechoic fascia separating the biceps femoris from the adductor muscle. The hypoechoic structure formed by the bupivacaine dye solution around the nerve was effectively visualized using ultrasound imaging. Sciatic nerve staining was successfully achieved in all pelvic limbs, with dye spread of 4.82 ± 1.55 mm and 5.47 ± 2.18 mm in groups 0.1 and 0.2, respectively (p = 0.128). CONCLUSIONS AND CLINICAL RELEVANCE: This study achieved a detailed understanding of the sonoanatomy of the sciatic nerve and its adjacent structures, highlighting the feasibility of the ultrasound-guided technique for injection in Wistar rats. Furthermore, the results show a comparable distribution of dye solution in both groups. Use of the ultrasound-guided sciatic nerve block technique in rats not only exhibits substantial potential for regional anesthesia but also opens avenues for translational studies.

Ultrasound-guided and 'blind' sciatic nerve injection techniques: Comparison in rat cadavers.

OBJECTIVE: To compare the success rate and extent of sciatic nerve staining with a bupivacaine-dye solution using two injection techniques: 'blind' or ultrasound-guided approach. STUDY DESIGN: Prospective, experimental, randomized, cadaveric study. ANIMALS: Adult female Wistar rat cadavers [n = 24, mass 352 g (323-374)]. METHODS: Each sciatic nerve was randomly allocated to one of two groups: 'blind' (group B) or ultrasound-guided approach (group US) to injection. Following injection of bupivacaine-dye solution (0.1 mL), gross anatomical dissection was performed to visualize nerve staining, categorizing it as either positive or negative. The length of nerve staining was then measured and visual inspection conducted to identify potential nerve damage. Fisher's exact test was used to compare positive or negative nerve staining, and the Wilcoxon signed rank test used to compare the length of nerve staining between groups. RESULTS: In group B, the bupivacaine-dye solution stained 16/24 sciatic nerves (67% success). In group US, staining was successfully observed in all 24 nerves (100% success, p < 0.004). The length of nerve staining [median (interquartile range)] was 2 (2-3) mm in group B and 5 (4-6) mm in group US (p < 0.001). One sciatic nerve in group B had injectate distributed over 16 mm, suggestive of an intraneural injection. No signs of laceration or nerve damage were visible under 6× magnification in either group. CONCLUSIONS AND CLINICAL RELEVANCE: The ultrasound-guided approach for sciatic nerve injection demonstrated a higher success rate with superior injectate distribution when compared with the 'blind' approach. Ultrasound guidance is recommended over a 'blind' approach for sciatic nerve block in rats when possible.

Heparin as a Potential Therapeutic Substance for Post-Traumatic Stress Disorder.

In sexually mature male Wistar rats with modeled post-traumatic stress disorder, personalized characteristics of neurobiological reactions in the population of predator-induced stress-resilient and stress-susceptible heparinized animals were determined. Characteristics of the systemic response of immune mechanisms, hypothalamic-pituitary-adrenal axis, behavioral manifestations, as well as basic properties of the CNS (excitation/inhibition) are presented. The study demonstrated encouraging positive results of the course administration of unfractionated heparin at a dose below the therapeutic and prophylactic doses. The inclusion of heparin drugs into the clinical practice for the treatment of post-traumatic stress disorder will not require large-scale clinical trials, because many effects of heparin as a nonspecific adaptogen are well studied. Moreover, these properties were confirmed at a higher technological level during the COVID-19 pandemic.

Evaluation of cilnidipine-loaded self-micro-emulsifying drug delivery system (SMEDDS) by quantification of comparative pharmacokinetic parameters using validated LC-ESI-MS/MS bioanalytical method and pharmacodynamic assessment.

OBJECTIVE: Regardless of having desired therapeutic properties many of the recently approved drugs are removed from the developmental pipeline for their clinical use due to low solubility and permeability. Conventional dosage forms are found relatively unsuitable for achieving desired pharmacokinetic and pharmacodynamics profiles. Cilnidipine is 1,4 dihydropyridine derivative calcium channel blocker used for the treatment of hypertension. METHOD: The aim and objective of this study was to develop a precise and significant method in LC-MS/MS for quantification of pharmacokinetic parameters of a cilnidipine-loaded self-micro-emulsifying drug delivery system in rat plasma and simultaneously assessed pharmacodynamic characters in comparison with the marketed cilnidipine tablet. Another potential aim of this study is to reduce the dose of the drug in order to counter the dose-dependent toxicities related to chronic use. In the present study, the parent and product ion of cilnidipine was m/z 491.3\237.1. RESULT: The plasma was extracted by protein precipitation technique. The calibration standard concentrations were 1.875, 3.75, 7.50, 15.00, 30.00, 60.00ng/mL and LLOQ, low-quality control, middle-quality control and high-quality control were 1.87, 5.62, 22.50, 45.00ng/mL, respectively. The mobile phase composition was 0.1% formic acid in Milli Q water with 10mM Ammonium acetate as an aqueous solvent and 0.1% formic acid in methanol as an organic solvent. Following oral administration of optimized formulation Cmax (peak plasma concentration) was achieved 21.02±3.17ng/mL at 0.866±0.11h (Tmax), whereas in the case of marketed tablet Cmax (peak plasma concentration) was achieved 10.16±0.89ng/mL at 0.93±0.11h (Tmax). DISCUSSION: The in-vivo characterizations of the optimized SMEDDS showed significantly better pharmacokinetic parameters in Wistar rats and showed almost 2.4 times enhanced relative bioavailability as compared to the marketed tablet of cilnidipine which was observed to be correlating to our findings with noninvasive blood pressure parameter of Wistar rats.

Swimming and L-arginine loaded chitosan nanoparticles ameliorates aging-induced neuron atrophy, autophagy marker LC3, GABA and BDNF-TrkB pathway in the spinal cord of rats.

Aging is associated with muscle atrophy, and erosion and destruction of neuronal pathways in the spinal cord. The study aim was to assess the effect of swimming training (Sw) and L-arginine loaded chitosan nanoparticles (LA-CNPs) on the sensory and motor neuron population, autophagy marker LC3, total oxidant status/total antioxidant capacity, behavioural test, GABA and BDNF-TrkB pathway in the spinal cord of aging rats. The rats were randomized to five groups: young (8-weeks) control (n = 7), old control (n = 7), old Sw (n = 7), old LA-CNPs (n = 7) and old Sw + LA-CNPs (n = 7). Groups under LA-CNPs supplementation received 500 mg/kg/day. Sw groups performed a swimming exercise programme 5 days per week for 6 weeks. Upon the completion of the interventions the rats were euthanized and the spinal cord was fixed and frozen for histological assessment, IHC, and gene expression analysis. The old group had more atrophy in the spinal cord with higher changes in LC3 as an indicator of autophagy in the spinal cord compared to the young group (p < 0.0001). The old Sw + LA-CNPs group increased (improved) spinal cord GABA (p = 0.0187), BDNF (p = 0.0003), TrkB (p < 0.0001) gene expression, decreased autophagy marker LC3 protein (p < 0.0001), nerve atrophy and jumping/licking latency (p < 0.0001), improved sciatic functional index score and total oxidant status/total antioxidant capacity compared to the old group (p < 0.0001). In conclusion, swimming and LA-CNPs seems to ameliorate aging-induced neuron atrophy, autophagy marker LC3, oxidant-antioxidant status, functional restoration, GABA and BDNF-TrkB pathway in the spinal cord of aging rats. Our study provides experimental evidence for a possible positive role of swimming and L-arginine loaded chitosan nanoparticles to decrease complications of aging.

Salsolinol Protects SH-SY5Y Cells Against MPP+ Damage and Increases Enteric S100-Immunoreactivity in Wistar Rats.

A dopamine derivative, 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, known as salsolinol (SAL), has increasingly gained attention since its first detection in the urine of Parkinson's disease patients treated with levodopa, and has been proposed as a possible neurotoxic contributor to the disease. Yet, so far, the neurobiological role of SAL remains unclear. Thus, the main aims of our study were to compare the neurotoxic potential of SAL with MPP+ (1-methyl-4-phenylpyridinium ion) in vitro, and to examine intestinal and metabolic alterations following intraperitoneal SAL administration in vivo. In vitro, SH-SY5Y neuroblastoma cell line was monitored following MPP+ and SAL treatment. In vivo, Wistar rats were subjected to SAL administration by either osmotic intraperitoneal mini-pumps or a single intraperitoneal injection, and after two weeks, biochemical and morphological parameters were assessed. SH-SY5Y cells treated with MPP+ (1000 µM) and SAL (50 µM) showed increase in cell viability and fluorescence intensity in comparison with the cells treated with MPP+ alone. In vivo, we predominantly observed decreased collagen content in the submucosal layer, decreased neuronal density with comparable ganglionic area in the jejunal myenteric plexus, and increased glial S100 expression in both enteric plexuses, yet with no obvious signs of inflammation. Besides, glucose and triglycerides levels were lower after single SAL-treatment (200 mg/kg), and low- to high-density lipoprotein (LDL/HDL) ratio and aspartate to alanine aminotransferases (AST/ALT) ratio levels were higher after continuous SAL-treatment (200 mg/kg in total over 2 weeks). Low doses of SAL were non-toxic and exhibited pronounced neuroprotective properties against MPP+ in SH-SY5Y cell line, which supports the use of SAL as a reference compound for in vitro studies. In vivo results give insight into our understanding of gastrointestinal remodeling following intraperitoneal SAL administration, and might represent morphological correlates of a microglial-related enteric neurodegeneration and dopaminergic dysregulation.

Nine-month-long Social Isolation Changes the Levels of Monoamines in the Brain Structures of Rats: A Comparative Study of Neurochemistry and Behavior.

Social isolation (SI) is chronic psycho-emotional stress for humans and other socially living species. There are few comparative studies that have measured monoamine levels in brain structures in male and female rats subjected to SI. Existing data is highly controversial. In our recent study, we investigated behavioral effects of SI prolonged up to 9 months on a rather large sample of 69 male and female Wistar rats. In the present study, we measured the levels of monoamines-norepinephrine (NE), dopamine (DA), 5-hydroxytryptamine (5-HT), and DA and 5-HT metabolites-in the brain structures of 40 rats from the same sample. The single-housed rats of both sexes showed hyperactivity and reduced reactivity to novelty in the Open Field test, and impaired passive avoidance learning. Regardless of their sex, by the time of sacrifice, the single-housed rats weighed less and had lower pain sensitivity and decreased anxiety compared with group-housed animals. SI decreased NE levels in the hippocampus and increased them in the striatum. SI induced functional activation of the DA-ergic system in the frontal cortex and hypothalamus, with increased DA and 3-methoxytyramine levels. SI-related changes were found in the 5-HT-ergic system: 5-HT levels increased in the frontal cortex and striatum, while 5-hydroxyindoleacetic acid only increased in the frontal cortex. We believe that SI prolonged for multiple months could be a valuable model for comparative analysis of the behavioral alterations and the underlying molecular processes in dynamics of adaptation to chronic psychosocial stress in male and female rats in relation to age-dependent changes.

Safety evaluation of Veillonella atypica FB0054 with genotoxicity and subchronic toxicological studies.

Veillonella atypica is a nonmotile, nonsporulating anaerobic bacteria commonly found in various human biofilms. V. atypica FB0054 was isolated from the gastrointestinal tract of marathon runners, who have increased amounts of this species after athletic events. Interestingly, the consumption of this strain by rodents has been shown to increase their treadmill endurance, leading to the hypothesis that consumption of this species may improve athletic performance in humans as well. Further evaluation, in humans, of the usefulness of this strain should be preceded by safety studies. Therefore, the genotoxic and subchronic toxicological potential was evaluated as a contribution to this effort. Genotoxicity investigation was performed using the in vivo comet assay and in vivo mammalian micronucleus assay due to the anaerobic characteristic of the strain. A 90-day, repeated-dose oral toxicity study was performed in rats up to 2200 mg/kg bw/d to investigate general toxicity and identify any target organs. Mitsuoka buffer, a solution shown to preserve the viability of anaerobic bacteria, was used as the vehicle. All three studies revealed no toxicological effects from exposure to FB0054 was isolated from the gastrointestinal tract of marathon runners, who have increased amounts of this species after athletic events. Interestingly, the consumption of this strain by rodents has been shown to increase their treadmill endurance, leading to the hypothesis that consumption of this species may improve athletic performance in humans as well. Further evaluation, in humans, of the usefulness of this strain should be preceded by safety studies. Therefore, the genotoxic and subchronic toxicological potential was evaluated as a contribution to this effort. Genotoxicity investigation was performed using the in vivo comet assay and in vivo mammalian micronucleus assay due to the anaerobic characteristic of the strain. A 90-day, repeated-dose oral toxicity study was performed in rats up to 2200 mg/kg bw/d to investigate general toxicity and identify any target organs. Mitsuoka buffer, a solution shown to preserve the viability of anaerobic bacteria, was used as the vehicle. All three studies revealed no toxicological effects from exposure to FB0054 at the highest doses tested.

Experimental keratitis induced in rat by Acanthamoeba from distinct morphological groups/genotypes: a histological and immunohistochemical evaluation.

Species of the genus Acanthamoeba are free-living protozoans that occasionally act as parasites, causing a severe, progressive corneal infection termed Acanthamoeba keratitis (AK). The variable pathogenic potential among Acanthamoeba lineages has been shown by in vitro assays, but little is known about the behavior of different strains in animal models of AK. This work aimed to evaluate the infectivity of Acanthamoeba from distinct morphological groups and genotypes in a rat model of AK and apply an immunohistochemical technique for histological characterization of the lesions. Only a strain classified as group I/genotype T17, isolated from a soil source, caused ulcerated corneal lesions in two Wistar rats (n = 9) subjected to intrastromal inoculation. Two strains derived from AK human cases (group II/genotype T4 and group III/genotype T5) did not induce corneal lesions in the rats. A previous association of group II/genotype T4 trophozoites with lethally irradiated Escherichia coli did not influence the infectivity. A hyperimmune serum produced in Wistar rats was validated by an immunocytochemical technique using the three distinct strains and then applied for immunohistochemistry. The abundance of antigenic residues was observed in both corneas with keratitis, suggesting that the infectious process tended to resolve. Despite the low infection rate of the AK Wistar rat model, we produced an immunochemical tool with a potential diagnostic application. We also showed for the first time the ability of Acanthamoeba from T17 genotype to cause AK in experimental conditions.

Genotoxic and mutagenic potential of 7-methylxanthine: an investigational drug molecule for the treatment of myopia.

7-Methylxanthine (7-MX, CAS No. 552-62-5, purity 99.46%) is the first orally administered drug candidate, which showed anti-myopic activity in different pre-clinical studies. In the present study, we investigated the in-vivo genotoxic and mutagenic toxicity of 7-MX in Wistar rats using comet/single-cell gel electrophoresis, chromosomal aberration and micronucleus assays after oral administration. For the single-dose study (72 h), two doses of 7-MX 300 and 2000 mg/kg body weight were selected. For a repeated dose 28 d study, three doses (250, 500, and 1000 mg/kg) of 7-MX were selected. The doses were administered via oral gavage in the suspension form. Blood and major vital organs such as bone marrow, lung and liver were used to perform comet/single cell gel electrophoresis, chromosomal aberration, and micronucleus assays. The in-vitro Ames test was performed on TA98 and TA100 strains. In the chromosomal aberration study, a non-significant increase in deformities such as stickiness, ring chromosome, and endoreduplication was observed in bone marrow cells of 7-MX treated groups. These chromosomal alterations were observed upon treatment with doses of 2000 mg/kg single dose for 72 h and 1000 mg/kg repeated dose for 28 d. At a dose of 500 mg/kg, DNA damage in terms of tail length, tail moment, % tail DNA and the olive tail moment was also found to be non-significant in 7-MX treated groups. The Ames test showed the non-mutagenic nature of 7-MX in both strains of TA98 and TA100 of Salmonella typhimurium with or without metabolic activation. Thus, the present work is interesting in view of the non- genotoxicity and non-mutagenicity of repeated doses of 7-MX.

Protective effect of Chromobacterium violaceum and violacein against bone resorption by periodontitis.

OBJECTIVES: The aim of this study was to evaluate the potential protective effect of Chromobacterium violaceum and violacein against periodontitis, in experimental models. MATERIALS AND METHODS: A double-blind experimental study on the exposure to C. violaceum or violacein in experimentally ligature-induced periodontitis, as preventive factors against alveolar bone loss by periodontitis. Bone resorption was assessed by morphometry. Antibacterial potential of violacein was assessed in an in vitro assay. Its cytotoxicity and genotoxicity were evaluated using the Ames test and SOS Chromotest assay, respectively. RESULTS: The potential of C. violaceum to prevent/limit bone resorption by periodontitis was confirmed. Daily exposure to 106 cells/ml in water intake since birth and only during the first 30 days of life significantly reduced bone loss from periodontitis in teeth with ligature. Violacein extracted from C. violaceum was efficient in inhibiting or limiting bone resorption and had a bactericidal effect against Porphyromonas gingivalis in the in vitro assay. CONCLUSIONS: We conclude that C. violaceum and violacein have the potential to prevent or limit the progression of periodontal diseases, in an experimental model. CLINICAL RELEVANCE: The effect of an environmental microorganism with potential action against bone loss in animal models with ligature-induced periodontitis represents the possibility of understanding the etiopathogenesis of periodontal diseases in populations exposed to C. violaceum and the possibility of new probiotics and antimicrobials. This would imply new preventive and therapeutic possibilities.