Ameliorative potentials of diosmin and hesperidin fractions on chlorpyriphos-induced changes in reproductive hormones, sperm characteristics, and testicular glycogen in male Wistar rats.

Reproductive deficiency is a major outcome of pesticide exposure sequel to cellular oxidative damage to sex organs. Flavonoid possess potent antioxidant capacities to mitigate pesticide related cellular injury. The present investigation examined the mitigative effect of micronized purified fractions of diosmin and hesperidin on reproductive hormones, sperm parameters, and testicular glycogen in male Wistar rats after sub-chronic Chlorpyriphos (CPF) exposure. Twenty-five male Wistar rats (120-145 g) were randomly allocated five rats per group. Group I (DW) received distilled water (2 ml/kg), Group II (S/oil) received soya oil (2 ml/kg), Group III (DAF) received Daflon at 1000 mg/kg, Group IV (CPF) received Chlorpyriphos (7.74 mg/kg), and Group V (DAF + CPF) received Daflon (1000 mg/kg) followed by CPF (7.74 mg/kg) after 30 min of Daflon. This regimen was administered daily for 60 days. After cervical venesection under light chloroform anesthesia, blood samples were examined for levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone. Each rat's testicular tissue was quickly cut, collected, and glycogen evaluated. Sperm concentration, motility, morphology, and viability were measured in the right caudal epididymis. Results revealed that the untreated CPF group had significantly lower FSH, LH, testosterone, testicular glycogen, and sperm concentration. Additionally, CPF group sperm characteristics were abnormal compared to other groups. These reproductive hormones, testicular glycogen, and sperm parameters improved in the Daflon-treated groups. Hence, pre-treatment with flavonoid fractions of diosmin and hesperidin mitigated CPF-induced reproductive toxicity.

Developmental deficits in male rat pups caused by maternal and dietary administration of chlorpyriphos and cypermethrin: Melatonin's mitigating effect.

The ability of melatonin to reduce growth inadequacy induced by parental and nutritional combination administration to chlorpyriphos (Ch) and cypermethrin (Cy) was examined in male albino rats. Oral alimentation was given to gravid dams divided into six groups (n = 10; age: 12 weeks) from the first day of pregnancy to the 21st postnatal day. Distilled water (DW), Soya oil (SYO), and melatonin (MeL) groups were exposed to 2 mL/kg, 2 mL/kg, and 0.5 mg/kg, respectively; the Ch+Cy group was co-exposed to Ch (1.9 mg/kg of LD50) and Cy (7.5 mg/kg of LD50); the MChCy group was preconditioned with MeL (0.5 mg/kg), followed by co-exposure to Ch and Cy; and the ChCyM group was exposed to Ch and Cy and post treated with MeL. Male offspring rats were tested for ontogeny criteria at various points after accouchement. MeL pre- and post-administration reduced the variation in litter size and weight, number of live/dead pups, anogenital distance , crown-rump length, the timing of eye and ear openings, and testicular descent caused by fetal and nutritional co-administration to Ch+Cy in offspring male albino rats. MeL demonstrated preventive promise as a result of its apparent antioxidative capability.

Effect of daflon-500®, a flavonoid compound on chlorpyriphos-induced oxidative changes in the hypophysis and testes in adult male rats.

Alteration of redox status is one of the molecular pathways commonly associated with pesticide toxicity. Antioxidants, including those obtained from plant phenolics, have been shown to mitigate pesticide-induced cellular injury. The present study was aimed at evaluating the effect of daflon-500 ® , a flavonoid compound on sub-chronic chlorpyriphos-evoked changes in antioxidant and biochemical parameters in the hypophysis and testes of adult male rats. Twenty-five male albino rats were randomly divided into 5 groups of 5 animals each. Group I (DW) received distilled water (2 ml/kg); group II (SO) was dosed with soya oil (2 ml/kg); Group III (DAF) received daflon-500 ® at 1000 mg/kg ~ 1/5th of LD50 (≥ 5000 mg/kg); group IV (CP) was administered chlorpyriphos at 7.74 mg/kg ~ 1/10th of LD50 (77.4 mg/kg) while group V (DAF + CP) was previously treated with daflon-500 ® (1000 mg/kg) and then exposed to CP (7.74 mg/kg), 30 min later. Daily oral regimen administration was done for 60 days after which the animals were sacrificed by cervical venesection after light chloroform anesthesia. The hypophysis and testicular tissues were harvested, and their homogenates were analyzed for malondialdehyde, catalase and superoxide dismutase, and acetylcholinesterase levels. A significant increase in the hypophysis and testicular MDA concentrations, coupled with a decrease in the SOD, CAT, and AChE activities were observed in the CP group. The levels of these oxidative and biochemical parameters were alleviated in the group pretreated with Daflon-500 ® . Results of this study demonstrated that pre-treatment with Daflon-500 ® mitigated CP-induced alterations in oxidative and biochemical parameters apparently due to the antioxidant effect of the flavonoid compound.

Effect of zinc supplementation on chronic hepatorenal toxicity following oral exposure to glyphosate-based herbicide (Bushfire®) in rats.

OBJECTIVES: To assess the effects of zinc pretreatment on hepatorenal toxicity following chronic exposure to glyphosate-based herbicides in male rats. METHODS: Following zinc pretreatment (50 mg/kg and 100 mg/kg), 14.4 to 750 mg/kg of oral glyphosate (Bushfire® herbicide) was administered daily for 36 weeks. Thereafter, serum samples were obtained following jugular venipuncture. Liver and kidney samples were processed for histopathological examination. RESULTS: Serum aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase activity as well as levels of bicarbonate, calcium, creatinine were significantly increased following chronic exposure to Bushfire®. Serum levels of sodium, potassium, chloride, total protein, albumin, globulin and urea were unchanged. Moderate to severe coagulative necrosis of hepatocytes as well as glomerular and renal tubular necrosis were observed in herbicide-treated rats. Zinc pretreatment reduced the elevation of serum enzymes associated with hepatobiliary lesions, abrogated hypercalcemia and metabolic alkalosis, and mitigated serum accumulation of creatinine following Bushfire® exposure, but was ineffective in completely preventing histological lesions. CONCLUSION: Chronic Bushfire® exposure in rats caused hepatorenal toxicity. The effects of exposure on serum parameters were ameliorated by zinc pretreatment, but the histopathological changes associated with toxicity persisted in milder forms in zinc-pretreated animals.

Pancreatic function and histoarchitecture in Wistar rats following chronic exposure to Bushfire®: the mitigating role of zinc.

Objectives To assess the toxicopathologic effects of chronic exposure to the glyphosate-based herbicide Bushfire® on the pancreas of Wistar rats and the protective role of zinc. Methods We exposed the rats to daily doses of 14.4 to 750 mg/kg body weight of the glyphosate-based herbicide Bushfire® and to 50 or 100 mg/kg zinc, and measured blood glucose levels and serum insulin levels. Tissue samples were evaluated for histopathological alterations. Results Levels of both blood glucose and serum insulin increased in glyphosate-exposed rats, and moderate to severe degenerative changes were observed in both glandular pancreatic acinar cells and islets of Langerhans in all rats exposed to glyphosate. These effects were prevented by pretreatment with zinc. Conclusion Chronic exposure to glyphosate can alter pancreatic function and histoarchitecture, but zinc supplementation can mitigate these toxicopathologic effects.

Chronic co-exposure to chlorpyrifos and deltamethrin pesticides induces alterations in serum lipids and oxidative stress in Wistar rats: mitigating role of alpha-lipoic acid.

The study evaluated the effect of combination of chlorpyrifos (CPF) and deltamethrin (DLT) on serum lipid profiles and oxidative stress in rats, and the mitigating role of alpha-lipoic acid (ALA). Thirty male rats were used for the 120-day study. Serum samples obtained at termination were evaluated for the levels of triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), malondialdehyde (MDA), and the activities of antioxidant enzymes. The levels of low-density lipoprotein-cholesterol (LDL), very low-density lipoprotein-cholesterol (VLDL), and atherogenic index (AI) were calculated. The pesticide combination elevated the levels of TG, TC, LDL, VLDL, AI, and MDA, and decreased HDL level, and activities of CAT, SOD, and GPx. The alterations induced by CPF and DLT were alleviated by ALA, partly through its antioxidant properties. In conclusion, co-exposure to DLT and CPF altered serum lipids and increased oxidative stress changes in the rats, which were ameliorated by ALA.

Dyslipdemia induced by chronic low dose co-exposure to lead, cadmium and manganese in rats: the role of oxidative stress.

Lead (Pb), cadmium (Cd) and manganese (Mn) have many potential adverse health effects in vitro and in animal models of clinical toxicity. The current study investigated the dyslipidaemic and oxidative stress effects of chronic low-dose oral exposure to Pb, Cd and Mn and the combination (Pb+Cd+Mn) in rats for 15 weeks. Chronic exposure to the metals did not significantly (P>0.05) alter serum lipid profiles. However, the atherogenic index decreased by 32.2% in the Pb+Cd+Mn group, relative to the control. The triglyceride/high-density lipoprotein cholesterol ratio decreased by 39.4% in the Pb+Cd+Mn group, relative to the control, and elevated by 81.8, 94.8 and 20.8%, relative to the Pb, Cd and Mn groups, respectively. While the serum concentrations of malondialdehyde significantly increased in the Mn and Pb+Cd+Mn groups, that of glutathione peroxidase-1 decreased in the Pb+Cd+Mn group, and metallothionein-1 and zinc concentrations markedly decreased in all the metal treatment groups. The results suggest that long-term exposure of rats to Pb+Cd+Mn may result in hypolipidaemia, mediated via oxidative stress and metal interactions. Individuals who are constantly exposed to environmentally relevant levels of the metals may be at risk of hypolipidaemia.

The protective role of alpha-lipoic acid on long-term exposure of rats to the combination of chlorpyrifos and deltamethrin pesticides.

The study was aimed at evaluating the protective role of α-lipoic acid (ALA) on long-term exposure of rats to the combination of chlorpyrifos (CPF) and deltamethrin (DLT). Forty-two (42) male Wistar rats were divided into 6 exposure groups with 7 animals in each group: (I) soya oil (2 ml kg-1), (II) ALA (60 mg kg-1), (III) DLT (6.25 mg kg-1), (IV) CPF (4.75 mg kg-1), (V) (CPF + DLT) DLT (6.25 mg kg-1) and CPF (4.75 mg kg-1; 1/20th of the previously determined median lethal dose) and (VI) (ALA + CPF + DLT) pretreated with ALA (60 mg kg-1) and then co-exposed to CPF and DLT, 45 min later. The regimens were administered by gavage once daily for a period of 16 weeks. Sera obtained from blood collected at the end of the experimental period were used for the evaluation of serum glucose, total protein, albumin, urea, creatinine and the activities of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase and acetylcholinesterase. The liver homogenate was used to assay for the activities of superoxide dismutase and glutathione peroxidase and the concentrations of malondialdehyde, cytokine and tumour necrotic factor α. The result showed that the combination of CPF and DLT resulted in marked alterations of these biochemical parameters in most cases compared to either of the pesticides singly, supplementation with ALA ameliorated these alterations.

Evaluation of hepatorenal impairments in Wistar rats coexposed to low-dose lead, cadmium and manganese: insights into oxidative stress mechanism.

The study aims to evaluate effects of chronic low-dose coexposure to lead (Pb), cadmium (Cd) and manganese (Mn) on hepatorenal toxicity and oxidative stress. Young male Wistar rats were treated with Pb acetate (1.4 mg/kg BW), Cd chloride (0.01 mg/kg BW), Mn chloride (0.14 mg/kg BW) and their combination (Pb + Cd + Mn) by oral gavage, for 15 weeks. Liver enzymes, albumin (Alb), globulin (Glb), total protein, creatinine, urea and electrolyte concentrations were measured in the serum. Hepatic and renal malondialdehyde (MDA), glutathione peroxidase-1 (GPx1) and metallothionein-1 (MT1) concentrations were measured by enzyme immunoassay technique. Chronic exposure to the metals significantly (p < .05) increased serum Glb concentration and decreased Alb/Glb ratio, compared to the controls. Serum creatinine concentration significantly (p < .05) decreased in the Pb, Cd and Pb + Cd + Mn groups, but elevated in the Mn group. Hepatic MDAs rose significantly (p < .05) in the Pb group, while hepatic GPx1 activities increased significantly (p < .05) in the Cd, Mn and Pb + Cd + Mn groups. Hepatic and renal MT1 concentration decreased (p < .05) in the Mn group only. Biochemical alterations were confirmed by light microscopy of the liver and kidneys, which showed degenerative changes. It is concluded that prolonged coexposure to environmentally relevant levels of Pb, Cd and Mn impairs liver and kidney functions via the induction of oxidative stress, and it underlines the importance of studying toxicants in combination.

Co-treatment of chlorpyrifos and lead induce serum lipid disorders in rats: Alleviation by taurine.

The aim of this study was to investigate the effects of taurine (TA) on serum lipid profiles following chronic coadministration of chlorpyrifos (CP) and lead acetate (Pb) in male Wistar rats. Fifty rats randomly distributed into five groups served as subjects. Distilled water (DW) was given to DW group, while soya oil (SO; 1 mL kg(-1)) was given to SO group. The TA group was treated with TA (50 mg kg(-1)). The CP + Pb group was administered sequentially with CP (4.25 mg kg(-1); 1/20th median lethal dose (LD50)) and Pb at 233.25 mg kg(-1) (1/20th LD50), while the TA + CP + Pb group received TA (50 mg kg(-1)), CP (4.25 mg kg(-1)), and Pb (233.25 mg kg(-1)) sequentially. The treatments were administered once daily by oral gavage for 16 weeks. The rats were euthanised, and the blood samples were collected at the termination of the study. Sera obtained from the blood samples were analyzed for total cholesterol, high-density lipoprotein cholesterol, triglycerides, and malondialdehyde, and also the activities of serum antioxidant enzymes including superoxide dismutase, catalase and glutathione peroxidase were analyzed. The low-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol, and atherogenic index were calculated. The results showed that CP and Pb induced alterations in the serum lipid profiles and evoked oxidative stress. TA alleviated the disruptions in the serum lipid profiles of the rats partially by mitigating oxidative stress. It was concluded that TA may be used for prophylaxis against serum lipid disorders in animals that were constantly co-exposed to CP and Pb in the environment.

Hemato-biochemical responses to packing in donkeys administered ascorbic acid during the harmattan season.

Experiments were performed to investigate the effect of ascorbic acid (AA) in reducing hemato-biochemical changes in pack donkeys during the cold-dry (harmattan) season. Six experimental donkeys administered orally AA (200 mg/kg) and six control donkeys not administered ascorbic acid were subjected to packing. Blood samples were collected from all donkeys for hematological and biochemical analyses. In the control donkeys, packed cell volume (PCV), erythrocyte count and hemoglobin concentration (Hb) decreased significantly (P<0.05) at the end of packing. In the experimental donkeys, there was no significant difference between the pre- and post-packing values of PCV, erythrocyte count and Hb. In the control donkeys, the neutrophil and neutrophil:lymphocyte ratio increased significantly (P<0.05) post packing, but in the experimental donkeys, the pre- and post-packing values were not significantly different. The eosinophil count increased significantly (P<0.05) in experimental and control donkeys post packing. In conclusion, packing exerted significant adverse effects on the hematological parameters ameliorated by AA administration. AA may modulate neutrophilia and induce a considerable alteration of erythroid markers in donkeys subjected to packing during the harmattan season.

Influence of zinc supplementation on histopathological changes in the stomach, liver, kidney, brain, pancreas and spleen during subchronic exposure of Wistar rats to glyphosate.

A subchronic toxicity study was carried out to determine the glyphosate-induced histopathological changes in the stomach, liver, kidney, brain, pancreas and spleen of rats and the attendant ameliorative effect when pretreated with zinc at the dose rate of 50 mg/kg body weight. The rats were exposed to two doses of the glyphosate (375 and 14.4 mg/kg body weight) for the period of 8 weeks which was the duration of the study, and some groups were exposed to the glyphosate after pretreatment with zinc. The histopathological changes recorded during the study were only in the rats exposed to the glyphosate at the dose rate of 375 mg/kg body weight except the vacuolation encountered in the brains and haemosiderosis in the spleens of rats exposed to zinc alone. Degenerated mucosal epithelial cells which involved the muscularis mucosa and the glands in the stomachs of rats were seen microscopically. Hepatic cells degeneration especially at the portal areas of the livers of rats was observed. The histopathological examination of the kidneys showed glomerular degeneration, mononuclear cells infiltration into the interstices of the tubules and tubular necrosis. The conspicuous changes seen in the brains were neuronal degeneration. Pancreatic acinar cells were degenerated while the spleen of the rats showed depopulated splenic cells in both the red and the white pulps. It was concluded that zinc supplementation in rats prior to glyphosate exposure ameliorated the histopathological changes observed in the stomach, liver, kidney, brain, pancreas and spleen with no observable alteration in the histoarchitecture in the organs of the zinc-supplemented rats.

Effects of melatonin on changes in cognitive performances and brain malondialdehyde concentration induced by sub-chronic co-administration of chlorpyrifos and cypermethrin in male Wister rats.

OBJECTIVE: To evaluate the ameliorative effect of melatonin on sub-chronic chlorpyrifos (CPF) and cypermethrin (CYP)-evoked cognitive changes in male Wistar rats. METHODS: Fifty adult male Wistar rats, divided into five groups of ten rats each, were used for the study. Groups 1 and II were given distilled water and soya oil (2 mL/kg) respectively. Group III was administered with melatonin at 0.5 mg/kg only. Group IV was administered with CPF [7.96 mg/kg (1/10th LD50)] and CYP [29.6 mg/kg (1/10th LD50)], and Group V was administered with CPF [7.96 mg/kg (1/10th LD50)] and CYP [29.6 mg/kg (1/10th LD50)] 30 min after melatonin (0.5 mg/kg). The regimens were administered by gavage once daily for 12 weeks. Thereafter, cognitive performances were determined and the brain was evaluated for malonaldehyde concentration. RESULTS: CPF and CYP induced cognitive deficits and increased brain malonaldehyde concentration, which were all ameliorated by melatonin. CONCLUSION: Cognitive deficits elicited by CPF and CYP was mitigated by melatonin due to its antioxidant property.

Serum biochemical assessment of hepatic and renal functions of rats during oral exposure to glyphosate with zinc.

A subchronic toxicity study was carried out to assess hepatic and renal functions of rats during oral exposure to glyphosate with zinc for the period of 8 weeks. Forty-eight Wistar rats used for the study were randomized into six groups of eight Wistar rats each, and each group had equal number of male and female Wistar rats. The Wistar rats administered with distilled water at 2 ml/kg body weight served as the control group (DW); others were administered with zinc at 50 mg/kg body weight (Z) group, glyphosate at 375 mg/kg body weight (G) group, a combination of zinc and glyphosate at 50 and 375 mg/kg body weight, respectively (Z + G), group, glyphosate at 14.4 mg/kg body weight (GC) group, and a combination of zinc and glyphosate at 50 and 14.4 mg/kg body weight, respectively (Z + GC), group. At the end of the study, blood samples were collected from each rats; from which, sera samples were obtained and assayed for total protein, albumin, alanine and aspartate aminotransferases, alkaline phosphatase, Na+, K+, Cl-, [Formula: see text], Ca2+, [Formula: see text], urea and creatinine using autoanalyzer, and globulin was calculated. The albumin concentration was significantly high (p < 0.05) in GC group compared to DW group, and this change was ameliorated following supplementation with zinc. The total protein and globulin concentrations did not differ significantly between the groups (p > 0.05), and the relative changes were ameliorated by supplementation with zinc. The alkaline phosphatase activity was relatively low in GC group; however, supplementation with zinc in Z + GC group made it to be significantly high (p < 0.05) compared to GC group. The alanine and aspartate aminotransferases in G and GC groups were relatively high compared to DW group, which were ameliorated by supplementation with zinc. The relatively low Ca2+ concentration in G and GC groups compared to DW were ameliorated in Z + G group, and it was significantly high in Z + GC group at p < 0.01 compared to DW, p < 0.001 compared to G and GC groups and p < 0.05 compared to Z + G group. There were only slight changes in the electrolytes concentrations (Na+, K+, Cl-, [Formula: see text] and [Formula: see text]), which were differentially ameliorated by zinc supplementation. The reasons for the various changes recorded were discussed. It was concluded that subchronic oral exposure to glyphosate caused both hepatic and renal functions toxicity in rats, which were ameliorated by zinc supplementation.

Flavonoid mixture ameliorates increase in erythrocyte osmotic fragility and malondialdehyde concentration induced by Trypanosoma brucei brucei-infection in Wistar rats.

The experiment was performed with the aim of investigating the effect of a flavonoid mixture, Daflon® 500 mg (DF) on the erythrocyte fragility and lipoperoxidative changes, induced by Trypanosoma brucei brucei infection in Wistar rats. Fifty adult male rats randomly divided into five groups of 10 animals each were used. Rats in the control group were administered (1 mL/kg) distilled water only, while the other groups were infected with T. brucei brucei and treated with Daflon® 500 mg and/or Diminazene aceturate. At the end of 5 weeks, EDTA-blood samples and serum samples were collected from the rats, and were used to determine erythrocyte osmotic fragility (EOF) and serum malondialdehyde (MDA) concentration respectively. The results showed that EOF and MDA concentration significantly (P<0.05) increased in the infected untreated group when compared to the treatment groups. Treatment with Daflon® 500 mg and Diminazene aceturate significantly (P<0.05) reduced trypanosome-induced increases in EOF and lipoperoxidative changes, suggesting possible antioxidant properties of Daflon® 500 mg and its therapeutic value in trypanosomosis.

Erythrocyte osmotic fragility and lipid peroxidation following chronic co-exposure of rats to chlorpyrifos and deltamethrin, and the beneficial effect of alpha-lipoic acid.

The present study aimed to evaluate the effect of chronic co-exposure to chlorpyrifos (CPF) and deltamethrin (DLT) on erythrocyte osmotic fragility, lipid peroxidation and the ameliorative effect of alpha-lipoic acid (ALA) on erythrocyte fragility. Thirty-six male Wistar rats divided into six groups of six rats each were used for the study. Groups I (S/oil) and II (ALA) were given soya oil (2 ml/kg) and ALA (60 mg/kg), respectively. Rats in group III (DLT) and IV (CPF) were exposed to DLT (6.25 mg/kg) and CPF (4.75 mg/kg) (1/20th of the previously determined LD50 of 125 mg/kg and 95 mg/kg, respectively, over a period of 48 h). Rats in group V (CPF + DLT) were co-exposed to CPF (4.75 mg/kg) and DLT (6.25 mg/kg), while those in group VI (ALA + CPF + DLT) were pretreated with ALA (60 mg/kg) and then co-exposed to CPF and DLT, 45 min later. The treatments were administered by gavage once daily for a period of 16 weeks. Blood collected at the end of the experimental period were analyzed for erythrocyte osmotic fragility and malondialdehyde (MDA) concentration. The study showed that chronic co-exposure to CPF and DLT resulted in an increase in erythrocyte fragility and MDA concentration which were ameliorated by supplementation with alpha-lipoic acid. The study concluded that repeated co-exposure to CPF and DLT elevated erythrocyte fragility probably due to increased lipid peroxidation, and pretreatment with alpha-lipoic acid ameliorated these alterations.

Effects of melatonin on changes in cognitive performances and brain malondialdehyde concentration induced by sub-chronic co-administration of chlorpyrifos and cypermethrin in male Wister rats

<p><b>OBJECTIVE</b>To evaluate the ameliorative effect of melatonin on sub-chronic chlorpyrifos (CPF) and cypermethrin (CYP)-evoked cognitive changes in male Wistar rats.</p><p><b>METHODS</b>Fifty adult male Wistar rats, divided into five groups of ten rats each, were used for the study. Groups 1 and II were given distilled water and soya oil (2 mL/kg) respectively. Group III was administered with melatonin at 0.5 mg/kg only. Group IV was administered with CPF [7.96 mg/kg (1/10th LD50)] and CYP [29.6 mg/kg (1/10th LD50)], and Group V was administered with CPF [7.96 mg/kg (1/10th LD50)] and CYP [29.6 mg/kg (1/10th LD50)] 30 min after melatonin (0.5 mg/kg). The regimens were administered by gavage once daily for 12 weeks. Thereafter, cognitive performances were determined and the brain was evaluated for malonaldehyde concentration.</p><p><b>RESULTS</b>CPF and CYP induced cognitive deficits and increased brain malonaldehyde concentration, which were all ameliorated by melatonin.</p><p><b>CONCLUSION</b>Cognitive deficits elicited by CPF and CYP was mitigated by melatonin due to its antioxidant property.</p>

Rectal temperature responses of donkeys administered with ascorbic acid and subjected to load carrying (packing) during the harmattan season in Nigeria.

The aim of the experiment was to evaluate the effect of 4-h load carrying (packing) on donkeys administered with ascorbic acid (AA) during the harmattan season. Six donkeys administered orally with ascorbic acid (200 mg/kg) and subjected to packing served as experimental animals, while six others given only distilled water served as control animals. The rectal temperature (RT) of each donkey and dry-bulb temperature (DBT) and relative humidity (RH) of the research pen were recorded at 0600 hours pre-packing; while post-packing, the values were obtained at 1430, 1600 and 1800 hours. The DBT values (ranges) recorded before, during and after packing were 13.7 ± 1.3 °C (11-15 °C), 28.4 ± 1.0 °C (22.7-30.3 °C) and 30.6 ± 3.0 °C (19.8-45 °C), respectively. The highest temperature-humidity index (THI) of 83.4 ± 6.9 was obtained at 1430 hours after packing, and the value decreased to 64.2 ± 5.8 at 1800 hours. The thermal environmental conditions were outside the thermoneutral zone for the donkeys. The RT values recorded immediately after packing did not differ (P > 0.05) in experimental and control donkeys; but at 1600 and 1800 hours, values obtained in control donkeys (38.48 ± 0.12 and 38.12 ± 0.12 °C, respectively) were significantly higher (P < 0.05) than those recorded in experimental donkeys (38.16 ± 0.14 and 37.85 ± 0.14 °C, respectively). In conclusion, administration of ascorbic acid reduced the rise in RT due to packing and may be of value in the amelioration of adverse effects of heat stress associated with work in donkeys.

Vitamin C Attenuates Chronic Chlorpyrifos-induced Alteration of Neurobehavioral Parameters in Wistar Rats.

BACKGROUND: Oxidative stress is one of the molecular mechanisms in chlorpyrifos toxicity. The present study was designed to evaluate the attenuating effect of vitamin C on chlorpyrifos-induced alteration of neurobehavioral performance and the role of muscle acetylchloinesterase (AChE), glycogen and lipoperoxidation in the accomplishment of this task. MATERIALS AND METHODS: Male rats were randomly assigned into 4 groups with the following regimens: soya oil (S/oil), vitamin C (VC), chlorpyrifos (CPF) and vitamin C+CPF (VC+CPF). The regimens were administered by gavage once daily for a period of 17 weeks. Neurobehavioral parameters measuring efficiency of locomotion, motor strength, righting reflex and excitability were evaluated at day 0 (pretreatment value), weeks 8 and 16. The rats were sacrificed at week 17 and evaluated for muscle glycogen and malonaldehyde (MDA) concentrations and AChE activity. RESULTS: The result showed that deficits in locomotion efficiency, motor strength, righting reflex and excitability score induced by chronic CPF were mitigated but not completely abolished by vitamin C. The reduced muscle AChE activity and concentrations of glycogen and MDA evoked by chronic CPF were ameliorated by vitamin C. CONCLUSION: The study therefore showed that improvement in muscle AChE activity, glycogen concentration and reduced lipoperoxidation by vitamin C may be partly responsible for the mitigation of the chronic CPF-induced sensorimotor performance.

Alleviating effects of melatonin on oxidative changes in the testes and pituitary glands evoked by subacute chlorpyrifos administration in Wistar rats.

OBJECTIVE: To evaluate the alleviating effects of melatonin on oxidative changes in the testes and pituitary gland induced by subacute chlopyrifos (CPF) exposure in rats. METHODS: Forty adult male Wistar rats divided into 4 groups of 10 animals were used for the study. Group I received soya oil (2 mL/kg) while group II was administered with melatonin (0.5 mg/kg). Group III was administered CPF only (8.5 mg/kg ∼ 1/10th of the LD50) while group IV was pretreated with melatonin (0.5 mg/kg) and then exposed to CPF (8.5 mg/kg), 10 min later. The regimens were administered by gavage once daily for a period of 28 d. At the end of the exposure period, the rats were sacrificed and the testicular tissues and pituitary glands were evaluated for the malonaldehyde (MDA) concentration and activities of superoxide dismutase (SOD) and catalase (CAT). RESULTS: CPF increased MDA concentrations and reduced the activities of SOD and CAT in the testes and pituitary gland. Melatonin pretreatment reduced the testicular and pituitary MDA concentrations and improves the SOD and CAT activities. CONCLUSIONS: the study showed that subacute CPF-induced oxidative stress in the testes and pituitary glands were alleviated by melatonin due to its antioxidant property.