Single and 90-day repeated oral dose toxicity studies of fermented Rhus verniciflua stem bark extract in Sprague–Dawley rats

Fermented Rhus verniciflua stem bark (FRVSB) extract, an urushiol-free extract of Rhus verniciflua Stokes (RVS) fermented with Fomitella fraxinea, has various biological activities. The present study was carried out to investigate the potential toxicity of the FRVSB extract following single and repeated oral administration to Sprague–Dawley rats. In the single dose toxicity study, the FRVSB extract was administered orally to male and female rats at single doses of 0, 2500, 5000, and 10,000 mg/kg. No animals died and no toxic changes were observed in clinical signs, body weight, and necropsy findings during the 15-day period following administration. In the repeated dose toxicity study, the FRVSB extract was administered orally to male and female rats for 90 days at doses of 0, 556, 1667, and 5000 mg/kg/day. There were no treatment-related adverse effects in clinical signs, body weight, food and water consumption, ophthalmic examination, urinalysis, hematology, serum biochemistry, necropsy findings, organ weight, and histopathology at any dose tested. The approximate lethal dose of the FRVSB extract was >10,000 mg/kg in both genders, the oral no-observed-adverse-effect level of the FRVSB extract was >5000 mg/kg/day in both genders, and no target organs were identified.     

Immunomodulatory activity of orphan drug Elmiron® in female B6C3F1/N mice

Interstitial cystitis (IC) is a chronic disorder characterized by bladder discomfort and urinary urgency in the absence of identifiable infection. Despite the expanding use in IC treatment and other chronic conditions, the effects of Elmiron® treatment on immune system remain unknown. Therefore, female B6C3F1/N mice were orally administered Elmiron® daily for 28-days at doses of 63, 125, 250, 500 or 1000 mg/kg to evaluate its immunomodulatory effects. Mice treated with Elmiron® had a significant increase in absolute numbers of splenic macrophages (63, 500 and 1000 mg/kg) and natural killer (NK) cells (250 and 1000 mg/kg). Elmiron® treatment did not affect the humoral immune response or T cell proliferative response. However, innate immune responses such as phagocytosis by liver macrophages (1000 mg/kg) and NK cell activity were enhanced (500 and 1000 mg/kg). Further analysis using a disease resistance model showed that Elmiron®-treated mice demonstrated significantly increased anti-tumor activity against B16F10 melanoma cells at the 500 and 1000 mg/kg doses. Collectively, we conclude that Elmiron® administration stimulates the immune system, increasing numbers of specific cell populations and enhancing macrophage phagocytosis and NK cell activity in female B6C3F1/N mice. This augmentation may have largely contributed to the reduced number of B16F10 melanoma tumors.     

Safety evaluation of a thermolysin enzyme produced from Geobacillus stearothermophilus

Thermolysin is a zinc metalloprotease that has potential uses in the food industry. The safety of thermolysin has not been demonstrated before, and therefore a series of standard toxicological tests to assess its potential toxicity was undertaken. The thermolysin used in this study was derived from the thermophilic bacterium Geobacillus stearothermophilus, which had undergone chemical mutagenesis to generate strains with increased thermolysin production. Acute toxicity studies in rats and mice showed that thermolysin powder is not acutely toxic with an oral LD₅₀ of more than 18,000 mg/kg (2520 mg/kg thermolysin protein) in rats and more than 24,000 mg/kg (3360 mg/kg protein) in mice. Subchronic feeding studies in rats for 91 days at doses up to 1000 mg/kg (390 mg/kg protein) revealed no significant differences between treated and non-treated groups and a No Observed Effect Level (NOEL) of 1000 mg/kg (390 mg/kg protein) per day was established. Results from genotoxicity tests such as in vitro chromosomal aberration assay and in vivo mouse micronucleus were negative. Allergenicity sequence analysis revealed no evidence suggesting that thermolysin is an allergen. The data presented in this study support the conclusion that thermolysin is safe for use in food production.     

Effects of pentoxifylline and alpha lipoic acid on methotrexate-induced damage in liver and kidney of rats

The aim of the current study was to investigate the probable protective effects of Pentoxifylline (PTX) and Alpha Lipoic Acid (ALA), which display anti-oxidative efficacy against hepatotoxicity and nephrotoxicity, those being the major side effects of Methotrexate (MTX). Rats were divided into four groups: a control group; MTX (20 mg/kg/day) group; MTX + PTX (20 mg/kg/day + 50 mg/kg/day) group; and an MTX + ALA (20 mg/kg/day + 100 mg/kg/day) group. At the end of the experiment, biochemical, histochemical and immunohistochemical analyses were performed on liver and kidney tissues of rats. We determined Glutathione Peroxidase (GSH-Px), Superoxide Dismutase (SOD), Catalase (CAT), Malondialdehyde (MDA), Nitric Oxide (NO) and Xanthine Oxidase (XO) levels in the liver and kidney. Moreover, Gamma Glutamyl Transferase (GGT), Direct Bilirubin (DBil), Blood Urea Nitrogen (BUN), and urea levels were measured in the serum. The histochemical evaluation revealed a significant decrease in MTX caused damage in the PTX- and ALA-treated groups (especially in ALA group). On the other hand, the immune staining of iNOS and TNF-α were observed most densely in the MTX group, while the density decreased in the PTX- and ALA-administered groups. We determined increased GGT, BUN, urea and levels of CAT, MDA, NO, and XO values in both groups, while GSH-Px (an increase in liver tissue) and DBil levels were decreased in the group that received MTX. However, we determined decreased SOD levels in liver tissue. In the PTX and ALA groups, the levels of GGT, BUN and urea as well as the levels of CAT, MDA, NO and XO decreased (SOD increased in the liver tissue), and the levels of GSH-Px and DBil increased. In conclusion, it can be stated that, although ALA is more effective in preventing the toxic effects of MTX on the liver and kidney, PTX also has a preventive effect. As a result, we can readily suggest that ALA and PTX can have protective effects by decreasing MDA, NO, BUN and urea values as antioxidants against MTX-induced damage in liver and kidney of rats.     

Acute and sub-chronic toxicity studies of the extract of Thunberg Fritillary Bulb

The aim of this study was to investigate the acute and sub-chronic toxicity of extract of Thunberg Fritillary Bulb. For the acute toxicity tests, graded doses of the extract were administered orally to mice. The animals were observed for toxic symptoms and mortality daily for 14 days. In the sub-chronic toxicity study, rats were orally administered the extract at doses of 1 and 3 mg/kg body weight (BW) for 26 weeks. After 26 weeks, the rats were sacrificed for hematological, biochemical and histological examination. In the acute toxicity tests, the estimated median lethal dosage (LD₅₀) was 52.2 mg/kg body weight in the mice. In the sub-chronic toxicity tests, a dose of 1 mg/kg body weight presented no toxicity. Above the 1 mg/kg dose, the main adverse signs observed in male rats were body or head tremor and spontaneous motor activity reduction. There were no other significant changes observed in hematology, blood biochemistry, organ weight and organ histology. The overall findings of this study indicate that the extract of Thunberg Fritillary Bulb is non-toxic up to 1 mg/kg body weight, which can be considered a safe application dose.     

Toxicological,toxicokinetic and gastroprotective evaluation of the benzaldehyde semicarbazone

Benzaldehyde semicarbazone (BS) has presented positive results in several pharmacological models, including anticonvulsivant and anti-inflammatory models. The present study evaluated the preclinical toxicity (acute and subchronic), as well as the toxicokinetic and gastroprotective effects of BS against ethanol lesions. Oral doses of 300 and 2000 mg/kg were used in the preclinical acute toxicity study; 100, 200, and 300 mg/kg were used in both the subchronic toxicity evaluation and the gastric study; and 300 mg/kg was used in the toxicokinetic study. No impact from the dose of 300 mg/kg could be identified; while, one animal died at 2000 mg/kg in the acute toxicity test. In the subchronic toxicity test, changes in the biochemical parameters of the liver, as well as in the histopatological evaluation, demonstrated that BS is a hepatotoxic drug. BS proved to be effective for moderate and severe gastric lesions. In the toxicokinetics study, BS presented a low concentration and rapid plasma disappearance. Several results also indicate that BS is likely to be mostly eliminated from the liver and may well undergo a first-pass effect after oral absorption. It was impossible to estimate the noobserved-adverse-effect-levels (NOAEL) and lowest-observed-adverse-effect-levels (LOAEL) due to the presence of hepatotoxicity in all tested doses.     

The effects of acute pharmacological stimulation of the 5-HT,NA and DA systems on the cognitive judgement bias of rats in the ambiguous-cue interpretation paradigm

In the present study, we investigated the effects of acute pharmacological stimulation of the serotonergic (5-HT), noradrenergic (NA) and dopaminergic (DA) systems on the valence of cognitive judgement bias of rats in the ambiguous-cue interpretation (ACI) paradigm. To accomplish this goal, after initial behavioural training, different groups of rats received single injections of citalopram, desipramine or d-amphetamine and were subsequently tested with the ACI paradigm. Each drug was administered in 3 doses using a fully randomised Latin square design. Citalopram at the dose of 1 mg/kg significantly biased animals towards positive interpretation of the ambiguous cue, while at higher doses (5 and 10 mg/kg), the animals interpreted the ambiguous cue more negatively. Desipramine at all 3 tested doses (1, 2 and 5 mg/kg) significantly biased animals towards negative interpretation of the ambiguous cue, while d-amphetamine at the dose of 1 mg/kg induced positive bias, having no effects at lower doses (0.1 and 0.5 mg/kg). Our results indicate that cognitive bias in rats can be influenced by acute pharmacological intervention.     

Protective effect of artemisinin on chronic alcohol induced-liver damage in mice

The liver disease related to chronic alcohol consumption is one of the leading causes of death for alcoholics. The efficient drug to ameliorate the alcoholic liver injury was needed urgently. The present study was performed to investigate whether artemisinin possessed the protective effect against chronic alcohol consumption. 50 male Kunming mice were divided into 5 groups: control group (C): 10 ml/kg saline + 10 ml/kg saline, alcohol group (A): 10 ml/kg 56%(v/v) alcohol + 10 ml/kg saline, low dose group of artemisinin (L): 10 ml/kg 56%(v/v) alcohol + 30 mg/kg/day artemisinin, medium dose group of artemisinin (M): 10 ml/kg 56%(v/v) alcohol + 60 mg/kg/day artemisinin, high dose group of artemisinin (H): 10 ml/kg 56%(v/v) alcohol + 120 mg/kg/day artemisinin. Drugs were given orally every day. The general state of mice was observed and the levels of serum activities of AST and ALT were detected after treatment with drugs for 30 days. Besides, the liver weight index was calculated and histopathological analysis was performed. We successfully demonstrated that treatment with high dose of artemisinin significantly decreased the elevated levels of AST (p < 0.05) and ALT (p < 0.01) in plasma, as well as the liver weight index (p < 0.01). The loss of body weight, tissue injury, oedema and inflammatory cell infiltration in the hepatocytes were found in the A group. These symptoms were remarkably alleviated in animals treated with artemisinin. Artemisinin can inhibit the activation of NF-кB and the expression of inflammatory cytokines inducible nitric oxide synthase. Besides, it can also enhance the stability of liver cell membrane, and reduce the damage of liver cell membrane and liver cell. Artemisinin showed a protective effect against chronic alcohol poisoning and it has a great potential for the clinical application to treat the liver injury induced by alcohol.     

Pre-clinical safety assessment of the synthetic human milk,nature-identical,oligosaccharide Lacto-N-neotetraose (LNnT)

Lacto-N-neotetraose (LNnT) is a tetrasaccharide naturally occurring in human breast milk, but not in cow’s milk. The safety data generated on a potential new LNnT ingredient produced by chemical synthesis is presented. Standard in vitro genotoxicity tests were performed. LNnT was also administered via gavage in 14-, 28- and 90-day studies at levels corresponding to 0 (control), 1000, 2500 and 5000 mg/kg bw/day in juvenile rats. Fructooligosaccharide (FOS) currently approved for use in infant formulae was used as a reference control at one dose level of 5000 mg/kg bw/day. LNnT was non-mutagenic in in vitro assays. Oral administration up to 5000 mg/kg bw/day to rats over 90 days was not associated with any adverse effects, based on clinical observations, body weight gain, feed consumption, clinical pathology, organ weights and histopathology findings. Regarding gastrointestinal effects, LNnT was better tolerated than FOS during the first 2 weeks of treatment. A No Observed Adverse Effect Level (NOAEL) of 5000 mg/kg bw/day for both male and female rats was identified for LNnT when administered by gavage for 90 days. These findings in the juvenile rat support the safety of LNnT for possible use in infant foods and allow further investigation in clinical studies.     

Effect of classic and atypical neuroleptics on cytochrome P450 3A (CYP3A) in rat liver

BackgroundCytochrome P450 3A (CYP3A) subfamily is involved in the metabolism of xenobiotics (e.g., drugs) and endogenous substances (e.g., steroids). The aim of the present study was to investigate the influence of classic and atypical neuroleptics on the level and activity of CYP3A in rat liver, measured as a rate of testosterone 2β- and 6β-hydroxylation.MethodsThe reactions were studied in control liver microsomes in the presence of neuroleptics, as well as in the microsomes of rats treated intraperitoneally (ip) with pharmacological doses of the drugs (promazine and thioridazine 10 mg/kg; chlorpromazine 3 mg/kg; haloperidol 0.3 mg/kg; risperidone 0.1 mg/kg; sertindole 0.05 mg/kg) for one day or two weeks (twice a day), in the absence of the neuroleptics in vitro.ResultsThe investigated neuroleptics added in vitro to control liver microsomes produced a moderate or week inhibitory effects on CYP3A activity. After one-day exposure of rats to neuroleptics, only chlorpromazine significantly increased the activity of CYP3A. Chronic treatment of rats with thioridazine diminished the protein level and activity of CYP3A, while risperidone induced this enzyme.ConclusionThe observed changes in the CYP3A expression after prolonged exposition to neuroleptics suggest their influence on the enzyme regulation.     

Activity of aminocandin (IP960; HMR3270) compared with amphotericin B,itraconazole, caspofungin and micafungin in neutropenic murine models of disseminated infection caused by itraconazole-susceptible and -resistant strains of Aspergillus fumigatus

Aminocandin (IP960; HMR3270; NXL201) is a new echinocandin with broad-spectrum in vitro activity against Aspergillus and Candida spp. We compared the activity of aminocandin with that of amphotericin B (AmB), itraconazole (ITC) and caspofungin (CAS) in murine models of disseminated aspergillosis against three strains of A. fumigatus, two of which were fully susceptible (AF293 and A1163) and one was resistant to ITC (AF91). Mice were rendered temporarily neutropenic or persistently neutropenic with cyclophosphamide and were infected intravenously 3 days later. Temporarily neutropenic mice were treated with either intraperitoneal (i.p.) AmB (5 mg/kg/dose), oral (p.o.) ITC (25 mg/kg/dose), intravenous (i.v.) aminocandin (0.25–10 mg/kg/dose), i.p. aminocandin (1 mg/kg/dose) or solvent control for 9 days. Mice were euthanised 11 days post infection and the kidneys and liver were removed for quantitative culture. Following infection with AF293, only aminocandin 5 mg/kg i.v. yielded 100% survival. Aminocandin 1 mg/kg i.v., AmB 5 mg/kg i.p. or ITC 25 mg/kg p.o. were equivalent (P > 0.05). Aminocandin 5 mg/kg was superior to aminocandin 0.25 mg/kg (P < 0.0001) as well as all controls (P < 0.0001) in reducing mortality. Following infection with AF91, only aminocandin at 5 mg/kg and 1 mg/kg i.v. yielded 100% survival, which was superior to ITC, aminocandin 0.25 mg/kg and controls (all P < 0.0001). In the persistently neutropenic model with A1163, aminocandin, CAS and micafungin (2–10 mg/kg) were all effective at prolonging survival, with some impact on reducing culture burdens, even with alternate-day dosing (4 mg/kg). The only fungicidal regimen was aminocandin 5 mg/kg, which sterilised 40% and 50% of mice following infection with AF293 and AF91, respectively. Aminocandin at doses of ≥1 mg/kg is highly effective in reducing mortality and organ burden in disseminated infection caused by ITC-susceptible and -resistant A. fumigatus.     

Disposition and acute toxicity of imidacloprid in female rats after single exposure

Single dose of imidacloprid (IMI-20 mg/kg bodyweight) was orally administered in female rats. Its disposition along with two metabolites 6-chloro nicotinic acid (6-CNA) and 6-hydroxy nicotinic acid (6-HNA) was monitored in organs (brain, liver, kidney, and ovary) and bodily fluids (blood, urine) at 6, 12, 24 and 48 h and faeces at 24 and 48 h. Maximum concentration (C_max) of IMI and metabolites in each organ and bodily fluid occurred after 12 h. Area under curve (AUC) of IMI ranged from 35 to 358 μg/ml/h; 6-CNA: 27.12–1006.42 μg/ml/h and 6-HNA: 14.98–302.74 μg/ml/h in different organs and bodily fluids. Clearance rate of IMI was maximum in ovary followed by kidney, liver, brain, faeces, blood and urine. Percent inhibition of acetyl-cholinesterase (AChE) was comparable in brain and Red Blood Cells (RBC) at 6–48 h which suggests the RBC-AChE as valid biomarker for assessing IMI exposure. It is evident that IMI was absorbed, metabolized, and excreted showing increased level of serum enzymes like Glutamic oxaloacetic transaminase (GOT), Glutamic pyruvic transaminase (GPT) and biochemical constituents like billirubin and Blood Urea Nitrogen (BUN) at 48 h. These data suggest that IMI is widely distributed, metabolized and induced toxicology effects at 20 mg/kg bodyweight to female rats.     

Acute and subacute toxicity studies on triptolide and triptolide-loaded polymeric micelles following intravenous administration in rodents

Except its anti-tumour effects, triptolide (TP) also shows multiple pharmacological side activities, such as immune-suppressive and male anti-fertility. To increase the therapeutic index of TP, a novel polymeric micelle system containing TP (TP-PM) has been developed to treat tumour. Our previous studies have demonstrated the good anti-tumour efficacy of TP-PM. This paper investigated the acute toxicity in mice and subacute toxicity in rats of TP-PM and TP. Results demonstrated that the LD₅₀ for TP-PM and TP administered intravenously were 1.06 mg/kg and 0.83 mg/kg in mice, respectively. In subacute toxicity study, TP-PM and TP were administered intravenously at the dose levels of 0.1 mg/kg and 0.3 mg/kg for 14 d. Compared to the control, there was significant decrease in the serum AST activities, the testis ACP activities, thymus index, testis index, and significant increase in spleen index, and obvious histopathological changes in rats treated with TP, however, the toxicities of TP-PM on liver, kidney, testis and spleen are slighter than TP. Compared to TP, TP-PM significantly increased the ACP activity of the testis and decreased the MDA level in serum. So, the polymeric micelles may be a novel drug delivery carrier of TP for reducing the toxicities of TP.     

Effects of paraoxon on serum biochemical parameters and oxidative stress induction in various tissues of Wistar and Norway rats

This study investigates the effects of different doses of paroxon (POX), an active metabolite of the organophosphate pesticide parathion, on some serum biochemical parameters and induction of oxidative stress in various tissues of female Wistar and Norway rats. The rats were intraperitoneally treated with 0.3, 0.7, 1 and 1.5 mg/kg of POX. The parameters were evaluated after 24 h. The results showed that the decreased glutathione level and catalase, glutathione-S-transferase and lactate dehydrogenase activities in tissues of Wistar rat were higher than Norway rat at higher doses of POX. At these concentrations, POX increased superoxide dismutase activity, malondialdehyde level and some serum biochemical indices. In conclusion, POX induces the production of free radicals and oxidative stress in a dose-dependent manner. Induction of oxidative stress in POX-treated rats is in the order of brain > liver > heart> kidney > spleen. Wistar rat is found to be more sensitive to the toxicity of POX compared to Norway rat.     

Safety profile of Hoodia gordonii extract: Mouse prenatal developmental toxicity study

Hoodia gordonii extract (0, 5, 15 or 50 mg/kg body weight/day, n = 24 mice/group) was orally administered by gavage to female CD-1 mice from gestation days 5–17. On gestation day 18 the females were euthanized and examined. Treatment at 50 mg/kg/day caused a marked reduction in feed intake and body weight gain. Feed consumption was sporadically reduced at 15 mg/kg/day. At 50 or 15 mg/kg/day fetal weights, ossification of some bones and full and empty uterus weights were reduced. There were no clear maternal or fetal effects at 5 mg/kg/day. Reproductive indices were unaffected at all doses and there were no treatment-related malformations, anomalies or variations. The overall study no-observed-adverse-effect level was set at 5 mg/kg/day.In summary, at doses that reduced maternal feed consumption, H. gordonii extract delayed fetal development. The fetal effects seen could be consequent to reduced maternal feed consumption, the desired biological activity of the test item.     

The immune responses in juvenile rockfish,Sebastes schlegelii for the stress by the exposure to the dietary lead (II)

The aim of this study was to evaluate the lead toxic effects on the stress parameters and immune responses of Sebastes schlegelii. Juvenile rockfish, S. schlegelii (mean length 14.2 ± 1.9 cm, and mean weight 57.3 ± 5.2 g) were exposed for 4 weeks with the different levels of dietary lead (Pb²⁺) at 0, 30, 60, 120 and 240 mg/L. The plasma cortisol and heat shock protein 70 was evaluated as stress indicators. The plasma cortisol of S. schlegelii was significantly increased in response to the dietary lead exposure over 60 mg/kg at 2 weeks. After 4 weeks, the significant increase in the plasma cortisol was observed at 30 and 60 mg/kg, but the level was decreased over 120 mg/kg. The heat shock protein 70 of S. schlegelii was also notably elevated over 60 mg/kg for 4 weeks. In the immune response, the immunoglobulin M of S. schlegelii was considerably increased over 120 mg/kg for 4 weeks. A significant increase was observed in lysozyme activity. The plasma lysozyme activity of S. schlegelii was elevated over 120 mg/kg after 2 weeks and 60 mg/kg after 4 weeks, and kidney lysozyme activity was also increased at 240 mg/kg after 2 weeks and over 120 mg/kg after 4 weeks. The results indicate that dietary Pb exposure can cause a significant stress and immune stimulation of S. schlegelii.     

Subchronic and reproductive toxicity of whole dried Hoodia parviflora aerial parts in the rat

Hoodia parviflora is being developed commercially for use in weight loss food and dietary supplement products. As part of the safety assessment process for H. parviflora, a freeze dried powder preparation was tested in a 90-day oral toxicity study with reproductive/recovery component in rats. Groups of 10 male and female Sprague–Dawley rats were administered H. parviflora dried powder at doses of 0, 100, 250, and 350 mg/kg body weight/day by gavage for an 11-week pre-mating period and a 14-day co-habitation period, and for females, through lactation day 4. An additional 5 rats/sex/group received 0 or 350 mg/kg bw/day for 90 days and were sacrificed 28 days after cessation of treatment. Statistically significant, non-adverse reductions in body weight, body weight gain, food consumption and food efficiency were observed at 250 and 350 mg/kg/day in females. Food consumption was reduced in high-dose males. There were no adverse effects on hematological, blood biochemical, coagulation or urinalysis parameters or on the results of the functional observational battery and histopathological examinations. No evidence of any effect was noted on reproductive or developmental parameters. The NOAEL for dried H. parviflora powder was 350 mg/kg bw/day, the highest permissible dose tested, for both male and female rats.     

Chronic administration of phenytoin induces efflux transporter overexpression in rats

BackgroundEfflux transporters overexpression has been proposed as one of the responsible mechanism for refractory epilepsy by preventing access of the antiepileptic drug to the brain. In this work we investigated whether phenytoin (PHT), could induce efflux transporters overexpression, at different biological barriers and to evaluate the implication it could have on its pharmacokinetics and therapeutic/toxic response.MethodsForty-two adult females Sprague Dawley divided in five groups were treated with oral doses of 25, 50 and 75 mg/kg/6 h of PHT for 3 days and two additionally groups were treated with intraperitoneal (ip) doses of 25 mg/kg/6 h or 100 mg/kg/24 h. At day 4 PHT plasma concentrations were measured and, obtained several organs, brain, parotid gland, liver and duodenum in which were analyzed for the Pgp expression. At day 4 PHT plasma concentrations were measured and several tissues: brain, parotid gland, liver and duodenum were obtained in order to analyze Pgp expression. In order to evaluate the oral bioavailability of PHT, two groups were administered with oral or intraperitoneal doses of 100 mg/kg and plasma level were measured.ResultsAn induction of the expression of efflux transporter mediated by phenytoin in a concentration-and-time dependent manner was found when increasing oral and ip doses of phenytoin, One week after the interruption of ip treatment a basal expression of transporters was recovered.ConclusionsOverexpression of efflux transporters can be mediated by inducer agents like PHT in a local-concentration dependent manner, and it is reversible once the substance is removed from the body. The recovery of basal Pgp expression could allow the design of dosing schedules that optimize anticonvulsant therapy.     

Effect of styrene exposure on plasma parameters,molecular mechanisms and gene expression in rat model islet cells

Styrene is an aromatic hydrocarbon compound present in the environment and have primary exposure through plastic industry. The current study was designed to evaluate styrene-induced toxicity parameters in rat plasma fasting blood glucose (FBG) level, oral glucose tolerance, insulin secretion, oxidative stress, and inflammatory cytokines in cellular and molecular levels. Styrene was dissolved in corn oil and administered at different doses (250, 500, 1000, 1500, 2000 mg/kg/day and control) to each rat, for 42 days. In treated groups, styrene significantly increased fasting blood glucose, plasma insulin (p < 0.001) and glucose tolerance. Glucose tolerance, insulin resistance and hyperglycemia were found to be the main consequences correlating gene expression of islet cells. Styrene caused a significant enhancement of oxidative stress markers (p < 0.001) and inflammatory cytokines in a dose and concentration-dependent manner in plasma (p < 0.001). Moreover, the activities of caspase-3 and −9 of the islet cells were significantly up-regulated by this compound at 1500 and 2000 mg/kg/day styrene administrated groups (p < 0.001). The relative fold change of GLUD1 was downregulated (p < 0.05) and upregulated at 1500 and 2000 mg/kg, respectively (p < 0.01). The relative fold changes of GLUT2 were down regulated at 250 and 1000 mg/kg and up regulated in 500, 1500 and 2000 mg/kg doses of styrene (p < 0.01). The expression level of GCK indicated a significant upregulation at 250 mg/kg and downregulation of relative fold changes in the remaining doses of styrene, except for no change at 2000 mg/kg of styrene for GCK. Targeting genes (GLUD1, GLUT2 and GCK) of the pancreatic islet cells in styrene exposed groups, disrupted gluconeogenesis, glycogenolysis pathways and insulin secretory functions. The present study illustrated that fasting blood glucose, insulin pathway, oxidative balance, inflammatory cytokines, cell viability and responsible genes of glucose metabolism are susceptible to styrene, which consequently lead to other abnormalities in various organs.