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Item Neuroprotective influence of taurine on fluoride-induced biochemical and behavioral deficits in rats(Elsevier Ireland Ltd., 2017) Adedara, I. A.; Abolaji, A. O.; Idris, U. F.; Olabiyi, B. F.; Onibiyo, E. M.; Ojuade, T. D.; Farombi, E. O.Epidemiological and experimental studies have demonstrated that excessive exposure to fluoride induced neurodevelopmental toxicity both in humans and animals. Taurine is a free intracellular b- amino acid with antioxidant and neuroprotective properties. The present study investigated the neu- roprotective mechanism of taurine by evaluating the biochemical and behavioral characteristics in rats exposed to sodium fluoride (NaF) singly in drinking water at 15 mg/L alone or orally co-administered by gavage with taurine at 100 and 200 mg/kg body weight for 45 consecutive days. Locomotor behavior was assessed using video-tracking software during a 10-min trial in a novel environment while the brain structures namely the hypothalamus, cerebrum and cerebellum of the rats were processed for biochemical determinations. Results showed that taurine administration prevented NaF-induced loco- motor and motor deficits namely decrease in total distance travelled, total body rotation, maximum speed, absolute turn angle along with weak forelimb grip, increased incidence of fecal pellets and time of grooming, immobility and negative geotaxis. The taurine mediated enhancement of the exploratory profiles of NaF-exposed rats was supported by track and occupancy plot analyses. Moreover, taurine prevented NaF-induced increase in hydrogen peroxide and lipid peroxidation levels but increased acetylcholinesterase and the antioxidant enzymes activities in the hypothalamus, cerebrum and cere- bellum of the rats. Collectively, taurine protected against NaF-induced neurotoxicity via mechanisms involving the restoration of acetylcholinesterase activity and antioxidant status with concomitant inhi- bition of lipid peroxidation in the brain of rats.Item Suppression of the brain-pituitary-testicular axis function following acute arsenic and manganese co-exposure and withdrawal in rats(Elsevier GmbH., 2017) Adedara, I. A.; Abolaji, A. O.; Awogbindin, I. O.; Farombi, E. O.Despite the fact that most environmental exposures to metals do not occur in isolation, the combined effects of metal mixtures on brain–pituitary–gonadal axis are poorly known. The present study investigated the impacts of co-exposure to arsenic (As) and manganese (Mn) on sperm characteristics, reproductive hormones and selected oxidative stress indices in the brain, testes and epididymis of rats following exposure for 15 consecutive days to 60 mg/L of AsO₃Na and 30 mg/L of MnCl₂ in drinking water. The results showed that while brain weight remained unaffected, the fluid intake and the weights of testes and epididymis significantly (p < 0.05) decreased in all the treatment groups. A significant decrease in the body weight gain when compared with control was noted only in the co-exposed rats. Moreover, the significant decreases in the antioxidant status in brain, testes and epididymis as well as in the circulatory concentrations of follicle-stimulating hormone, luteinizing hormone and testosterone were similar following separate or combined exposure of rats to As and Mn. The marked oxidative damage in the investigated tissues was accompanied by a significant decrease in the sperm quantity and quality in all the treated rats when compared with the control. Interestingly, most of the parameters determined immediately after the exposure period persisted in rats from the withdrawal experiment. Collectively, co-exposure to As and Mn suppressed the brain–pituitary–testicular axis function and the post-testicular events such as sperm function possibly via a mechanism involving persistent oxidative stress and endocrine disruption in the exposed rats.Item Quercetin improves neurobehavioral performance through restoration of brain antioxidant status and Acetylcholinesterase activity in Manganese-treated rats(Springer Science+Business Media, 2017) Adedara, I. A.; Ego, V. C.; Subair, T. I.; Oyediran, O.; Farombi, E. O.The present study investigated the neuroprotective mechanism of quercetin by assessing the biochemical and behavioral characteristics in rats sub-chronically treated with manganese alone at 15 mg/kg body weight or orally co-treated with quercetin at 10 and 20 mg/kg body weight for 45 consecutive days. Locomotor behavior was monitored using video-tracking software during a 10-min trial in a novel environment whereas the brain regions namely the hypothalamus, cerebrum and cerebellum of the rats were processed for biochemical analyses. Results indicated that co-treatment with quercetin significantly (p < 0.05) prevented manganese-induced locomotor and motor deficits specifically the decrease in total distance travelled, total body rotation, maximum speed, absolute turn angle as well as the increase in time of immobility and grooming. The improvement in the neurobehavioral performance of manganese-treated rats following quercetin co-treatment was confirmed by track and occupancy plot analyses. Moreover, quercetin assuaged manganese-induced decrease in antioxidant enzymes activities and the increase in acetylcholinesterase activity, hydrogen peroxide generation and lipid peroxidation levels in the hypothalamus, cerebrum and cerebellum of the rats. Taken together, quercetin mechanisms of ameliorating manganese-induced neurotoxicity is associated with restoration of acetylcholinesterase activity, augmentation of redox status and inhibition of lipid peroxidation in brain of rats.Item Benzo(a)pyrene induces oxidative stress, pro-inflammatory cytokines, expression of nuclear factor-kappa B and deregulation of wnt/beta- catenin signaling in colons of BALB/c mice201(Elsevier Ltd., 2016) Ajayi, B. O.; Adedara, I. A.; Farombi, E. O.The incidence of colonic toxicity has been epidemiologically linked to the consumption of foods contaminated with benzo[a]pyrene (B[a]P). The present study investigated the effects of B[a]P on biomarkers of colonic stress, inflammation and Wnt/β-catenin signaling in colon of BALB/c mice. B[a]P was administered orally at 62.5, 125 and 250 mg/kg of B[a]P for 7 days by oral gavage. Exposure to B[a]P significantly decreased the colonic antioxidant enzyme activities and glutathione levels with concomitant significant increase in myeloperoxidase activity, nitric oxide and lipid peroxidation levels. Colon histopathology results showed treatment-related lesions characterized by atrophy, mucosal ulceration and gland erosion in the B[a]P-treated mice. Immunohistochemistry analysis showed that B[a]P treatment increased the protein expression of nuclear factor kappa B, pro-inflammatory cytokines namely tumor necrosis factor alpha and interleukin-1β, as well as cyclooxygenase-2 and inducible nitric oxide synthase in the mice colon. Altered canonical Wnt signaling was confirmed using diaminobenzidine staining for p38 mitogen activated protein kinase, β-catenin expression and absence of adenomatous polyposis coli following B[a]P administration. The present data highlight that exposure to B[a]P induces colonic injury via induction of oxidative and nitrosative stress, inflammatory biomarkers and dysregulation of Wnt/β-catenin signaling, thus confirming the role of B[a]P in the pathogenesis of colonic toxicity.Item Dietary protocatechuic acid ameliorates dextran sulphate sodium-induced ulcerative colitis and hepatotoxicity in rats(The Royal Society of Chemistiy, 2016) Farombi, E. O. || || || || || || ||; Adedara, I. A.; Awoyemi, O. V.; Njoku, C. R.; Micah, G. O.; Esogwa, C. U.; Owumi, S. E.; Olopade, J. O.The present study investigated the antioxidant and anti-inflammatory effects of dietary protocatechuic acid (PCA), a simple hydrophilic phenolic compound commonly found in many edible vegetables, on dextran sulphate sodium (DSS)-induced ulcerative colitis and its associated hepatotoxicity in rats. PCA was administered orally at 10 mg kg-1 to dextran sulphate sodium exposed rats for five days. The result revealed that administration of PCA significantly (p < 0.05) prevented the incidence of diarrhea and bleed- ing, the decrease in the body weight gain, shortening of colon length and the increase in colon mass index in DSS-treated rats. Furthermore, PCA prevented the increase in the plasma levels of pro-inflamma- tory cytokines, markers of liver toxicity and markedly suppressed the DSS-mediated elevation in colonie nitric oxide concentration and myeloperoxidase activity in the treated rats. Administration of PCA significantly protected against colonie and hepatic oxidative damage by increasing the antioxidant status and concomitantly decreased hydrogen peroxide and lipid peroxidation levels in the DSS-treated rats. More- over, histological examinations confirmed PCA chemoprotection against colon and liver damage. Immunohistochemical analysis showed that PCA significantly inhibited cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) protein expression in the colon of DSS-treated rats. In conclusion, the effective chemoprotective role of PCA in colitis and the associated hepatotoxicity is related to its intrinsic anti-inflammatory and anti-oxidative properties.Item Neurobehavioral and biochemical changes in Nauphoeta cinerea following dietary exposure to chlorpyrifos(Elsevier Inc., 2016) Adedara, I. A.; Rosemberg, D. B.; Souza, D.; Farombi, E. O.; Aschner, M.; Souza, D. O.; Rocha, J. B. T.The present study aimed to increase our understanding about the mode of toxic action of organophosphate pesticides in insects by evaluating the biochemical and neurobehavioral characteristics in Nauphoeta cinerea exposed to chlorpyrifos (CPF)-contaminated diet. The insects were exposed for 35 consecutive days to CPF at 0.078, 0.15625, 0.3125 and 0.625 μg/g feed. Locomotor behavior was assessed for a 10-min trial in a novel arena and subsequently, biochemical analyses were carried out using the cockroaches’ heads. In comparison to control, CPF-exposed cockroaches showed significant decreases in the total distance traveled, body rotation, turn angle and meandering, along with significant increase in the number of falls, time and episodes of immobility. The marked decrease in the exploratory profiles of CPF-exposed cockroaches was confirmed by track plots, whereas occupancy plot analyses showed a progressive dispersion at 0.15625 μg/g feed group. Moreover, the heads of CPF-exposed cockroaches showed marked decrease in acetylcholinesterase activity and antioxidant status with concomitant significant elevation in dichlorofluorescein oxidation and lipid peroxidation levels in CPF-treated cockroaches. Gas Chromatography–Mass Spectrometry analyses revealed bioaccumulation of CPF in cockroaches exposed to concentrations above 0.078 μg/g feed. The findings from this investigation showed N. cinerea as a value model organism for the risk assessment of environmental organophosphate contamination in insects.Item Influence of diphenyl diselenide on chlorpyrifos-induced toxicity in Drosophila melanogaster(Elsevier GmbH., 2015) Adedara, I. A.; Klimaczewski, C. V.; Barbosa, N. B. V.; Farombi, E. O.; Souza, D. O.; Rocha, J. B. T.Exposure to chlorpyrifos (CPF) poses several harmful effects to human and animal health. The present study investigated the influence of diphenyl diselenide (DPDS) on CPF-induced toxicity in Drosophila melanogaster. Firstly, the cumulative responses of virgin flies (2- to 3-day-old) to CPF (0.075–0.6 µg/g) and DPDP (5–40 µmol/kg) in the diet for 28 consecutive days were investigated. Subsequently, the protective effect of DPDS (10, 20 and 40 µmol/kg) on CPF (0.15 µg/g)-induced mortality, locomotor deficits, neurotoxicity and oxidative stress was assessed in a co-exposure paradigm for 7 days. Results showed that CPF exposure significantly decreased the operant reflex in a time- and concentration-dependent manner, whereas the percent live flies with DPDS treatment was not statistically different from control following 28 days of treatment. In the co-exposure study, CPF significantly increased mortality while the survivors exhibited significant locomotor deficits with decreased acetylcholinesterase (AChE) activity. Dietary supplementation with DPDS was associated with marked decrease in mortality, improvement in locomotor activity and restoration of AChE activity in CPF-exposed flies. Moreover, CPF exposure significantly decreased catalase and glutathione-S-transferase activities, total thiol level with concomitant significant elevation in levels of reactive oxygen species and thiobarbituric acid reactive substances in the head and body regions of the treated flies. Dietary supplementation with DPDS significantly improved the antioxidant status and prevented CPF-induced oxidative stress, thus demonstrating the protective effect of DPDS in CPF-treated flies.Item Biochemical and behavioral deficits in the lobster cockroach Nauphoeta cinerea model of methylmercury exposure(The Royal Society of Chemistry, 2015) Adedara, I. A.; Rosemberg, D. B..; Souza, D. O.; Kamdem, J. P.; Farombi, E. O.; Aschnerd, M.; Rocha, J. B. T.Methylmercury (MeHg) is well-known for its neurodevelopmental effects both in animals and in humans. As an alternative to utilizing conventional animal models, this study evaluated behavioral and biochemical parameters using the nymphs of the lobster cockroach Nauphoeta cinerea. Animals were exposed to MeHg at 0, 0.03125, 0.0625, 0.125, 0.25 and 0.5 mg per g feed for 35 consecutive days. Locomotor activity and exploratory profiles were analyzed using video-tracking software during a 10 minute trial. Subsequently, biochemical estimations were carried out using cockroach heads. MeHg exposure caused behavioral impairment as evidenced by a significant decrease in distance travelled, time spent walking, turn angle and body rotation. The marked decrease in the exploratory profiles of MeHg-exposed cockroaches was confirmed by track plots, whereas occupancy plot analyses revealed a gradual dispersal in homebase formation, starting from 0.0625 mg per g feed. Biochemically, MeHg exposure significantly decreased acetylcholinesterase activity (AChE), an enzyme which plays a pivotal role in neurotransmission. Moreover, MeHg caused increased oxidative stress as evidenced by decreased total thiol levels and glutathione S-transferase (GST) activity, along with increased 2’,7’-dichlorofluorescein (DFCH) oxidation and thiobarbituric acid reactive substance (TBARS) production. In conclusion, these data demonstrated that Nauphoeta cinerea mimics the behavioral and biochemical deficits observed in rodents exposed to MeHg, thus highlighting its validity as an alternative model for basic toxicological studies.Item Municipal landfill Leachate-induced testicular oxidative damage is associated with biometal accumulation and endocrine disruption in rats(Springer Science+Business Media, 2015) Adedara, I. A.; Awogbindin, I. O.; Adesina, A. A.; Oyebiyi, O. O.; Lawal, T. A.; Farombi, E. O.Improper management of hazardous wastes adversely impacts the environment and the public health. The present study was aimed at investigating the influence of Olushosun municipal landfill leachate (OMLL) from Ojota in the Lagos State of Nigeria on testicular function by assessing the plasma concentrations of reproductive hormones, testicular biometal levels, and antioxidant levels as well as observing the histological alterations in testes and epididymides of rats after exposure to 0, 12.5, and 25 % OMLL in drinking water for 7 days. Exposure to OMLL significantly decreased the daily fluid intake, but it resulted in testicular biometal accumulation as follows: lead [cadmium[nickel[iron[copper. Acute exposure to OMLL induced oxidative stress and increased the activities of marker enzymes of testicular function but markedly decreased the circulatory concentrations of luteinizing hormone, follicle-stimulating hormone, prolactin, testosterone, thyroid-stimulating hormone, triiodothyronine, and thyroxine. Testicular and epididymal degeneration with significant decrease in sperm quality and quantity were observed in OMLL-exposed rats. Collectively, the data presented herein indicate that exposure to OMLL-induced testicular dysfunction associated with biometal accumulation and endocrine disruption in rats. If the effects can be extrapolated to humans, OMLL may present significant health implications for individuals exposed to OMLL-contaminated substances.Item Sperm functional parameters and erythrocytes oxidant–antioxidant imbalance during municipal landfill leachate treatment withdrawal in rats(Elsevier B.V., 2014) Adedara, I. A.; Lawal, T. A.; Adesina, A. A.; Oyebiyi, O. O.; Ebokaiwe, A. P.; Farombi, E. O.Adequate information on how leachates affect hematological and reproductive functions is necessary to help in linking causality with predictable response. The present study investigated the effects of Olushosun municipal landfill leachate (OMLL) exposure and withdrawal on sperm characteristics and erythrocytes oxidant–antioxidant balance in rats. Adult male Wistar rats were exposed to 0%, 12.5% and 25% OMLL in drinking water for 28 days. One half of the rats in each group were sacrificed on day 29 while the remaining one-half stayed an additional 28 days without treatment. OMLL exposure significantly decreased sperm functional parameters, disrupted antioxidant systems with concomitant elevation in hydrogen peroxide and malondial dehyde levels in erythrocytes and sperm. Following withdrawal of treatment, OMLL-mediated decrease in sperm count and daily sperm production were reversed to near control. However, erythrocytes and sperm oxidative damage, increased sperm abnormalities, decreased epididymis weight, sperm progressive motility and testicular sperm number persisted and were consistent with results obtained from rats sacrificed immediately after OMLL treatment. Collectively, OMLL-induced irreversible oxidative damage to erythrocytes and sperm in rats within the time course of investigation. These findings highlight potential adverse effects of OMLL on individuals unduly exposed to leachates contaminated substances.