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Item 4-Vinylcyclohexene diepoxide disrupts sperm characteristics, endocrine balance and redox status in testes and epididymis of rats(Informa UK Limited, 2017) Adedara, I. A.; Abolaji, A. O.; Ladipo, E. O.; Fatunmibi, O. J.; Abajingin, A. O.; Farombi, E. O.Objectives: Exposure to 4-vinylcyclohexene diepoxide (VCD) was reported to induce testicular germ cell toxicity in rodents. However, there is paucity of information on the precise biochemical and molecular mechanisms of VCD-induced male reproductive toxicity. Methodology: This study investigated the influence of VCD on testicular and epidydimal functions following oral exposure of Wistar rats to VCD at 0, 100, 250 and 500 mg/kg for 28 consecutive days. Results: Administration of VCD significantly decreased the body weight gain and organosomatic indices of the testes and epididymis. When compared with the control, VCD significantly decreased superoxide dismutase and catalase activities in the testes whereas it significantly decreased superoxide dismutase activity but increased catalase activity in the epididymis. Moreover, while glutathione peroxidase activity and glutathione level remain unaffected, exposure of rats to VCD significantly increased glutathione S-transferase activity as well as hydrogen peroxide and malondialdehyde levels in testes and epididymis of the treated rats. The spermiogram of VCD-treated rats showed significant decrease in epididymal sperm count, sperm progressive motility, testicular sperm number and daily sperm production when compared with the control. Administration of VCD significantly decreased circulatory concentrations of follicle-stimulating hormone, luteinizing hormone and testosterone along with testicular and epididymal degeneration in the treated rats. Immunohistochemical analysis showed significantly increased cyclooxygenase-2, inducible nitric oxide synthase, caspase-9 and caspase-3 protein expressions in the testes of VCDtreated rats. Conclusion: Exposure to VCD induces testicular and epidydimal dysfunctions via endocrine suppression, disruption of antioxidant enzymes activities, increase in biomarkers of oxidative stress, inflammation and apoptosis in rats.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 Redox status of the testes and sperm of rats following exposure to 2,5-hexanedione(Taylor & Francis Group, 2016) Adedara, I. A. || || || || ||; Abolaji, A. O.; Odion, B. E.; Omoloja, A. A.; Okwudi, I. J.; Farombi, E. O.Objectives: Exposure to 2, 5-hexanedione (2, 5-HD) is well known to be associated with reproductive dysfunctions in both humans and animals. However, the role of oxidative stress in 2, 5-HD-induced toxicity in testes and sperm has not yet been studied. Methodology: The present study investigated the influence of 2, 5-HD on antioxidant systems in the testes and epididymal sperm of rats following exposure to 0, 0.25, 0.5, and 1% 2, 5-HD in drinking water for 21 consecutive days. Results: Administration of 0.5% 2, 5-HD significantly (P < 0.05) decreased epididymis weight, whereas 1% 2, 5-HD-treated rats showed significantly decreased body weight, testis, and epididymis weights compared with the control group. Exposure to 2, 5-HD caused a significant dose-dependent increase in the activities of superoxide dismutase, catalase, and glutathione peroxidase in both testes and sperm compared with the control group. Moreover, 2, 5-HD-exposed rats showed significant decrease in glutathione-S-transferase activity and glutathione level with concomitant significant elevation in the levels of hydrogen peroxide and malondialdehyde in both testes and sperm. Testicular and epididymal atrophy with significant, dose-dependent, decrease in epididymal sperm number, sperm motility, and viability were observed in 2, 5-HD-treated rats. Conclusion: 2,5-HD exposure impaired testicular function and sperm characteristics by disruption of the antioxidant systems and consequently, increased oxidative stress in the treated rats.Item Impairment of hepatic and renal functions by 2,5-hexanedione is accompanied by oxidative stress in rats(Hindawi Publishing Corporation, 2014) Adedara, I. A. || ||| ||; Abolaji, A. O.; Odion, B. E.; Okwudi, I. J.; Omoloja, A. A.; Farombi, E. O.2,5-Hexanedione (2,5-HD) is the toxic metabolite of n-hexane which is widely used as solvent in numerous industries. The present study elucidated the precise mechanism of 2,5-HD in hepatorenal toxicity by determining the involvement of oxidative stress in rats. Adult maleWistar rats were exposed to 0, 0.25, 0.5, and 1% 2,5-HD in drinking water for 21 days. Exposure to 2,5-HD caused liver and kidney atrophy evidenced by significant elevation in serum aminotransferases, alkaline phosphatase, albumin, bilirubin, urea, creatinine, and electrolytes levels compared with control. The marked dose-dependent increase in total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL) was accompanied with significant decrease in high-density lipoprotein (HDL) levels in 2,5-HD-exposed animals when compared with the control. Administration of 2,5-HD significantly diminished glutathione (GSH) level but increased the activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and glutathione-Stransferase (GST) concomitantly with marked elevation in hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels in liver and kidney of the treated groups compared with control. These findings suggest that undue exposure to 2,5-HD at environmentally relevant levels may impair liver and kidney functions through induction of oxidative stress.Item Sperm characteristics, antioxidant status and hormonal profile in rats treated with artemisinin(Blackwell Verlag GmbH, 2013) Farombi, E. O.; Adedara, I. A.; Abolaji, A. O.; Anamelechi, J. P.; Sangodele, J. O.The indiscriminate use, abuse and patients’ noncompliance to normal prescription of artemisinin and its derivatives are a common practice during the treatment for drug-resistant malaria parasites in most developing countries. This study investigated the influence of artemisinin on the testicular and epididymal sperm antioxidant systems as well as on the plasma levels of hormones from the pituitary and thyroid components of the brain–pituitary–testicular axis. Oral exposure of rats to 0, 7 and 35 mg kg_1 artemisinin for 7 days showed that the testicular antioxidant status at both therapeutic dose (7 mg kg_1) and overdose (35 mg kg_1), and the sperm antioxidant status at therapeutic dose of artemisinin remained unaffected compared with control. However, increased hydrogen peroxide and lipid peroxidation levels were accompanied by a concomitant decrease in glutathione peroxidase and glutathione-S-transferase activities as well as glutathione level in spermatozoon of rats administered with overdose of artemisinin. While plasma levels of all the hormones investigated remained unaffected, severe epididymal degeneration with concomitant decrease in sperm quantity and quality was observed in rats treated with overdose of artemisinin compared with control. Overall, induction of oxidative stress in the epididymis, but not in the testes, could cause reproductive deficits in individuals unduly undergoing artemisinin therapy.