AMELIORATIVE EFFECTS OF MELATONIN ON SUBACUTE CHLORPYRIFOS-INDUCED REPRODUCTIVE TOXICITY IN MALE WISTAR RATS
AMELIORATIVE EFFECTS OF MELATONIN ON SUBACUTE CHLORPYRIFOS-INDUCED REPRODUCTIVE TOXICITY IN MALE WISTAR RATS
No Thumbnail Available
Date
2010-11
Authors
UMOSEN, ANGELA JECINTA AMA
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Studies were conducted to determine the effect of subacute chlorpyrifos exposure on semen characteristics and hormonal, biochemical and pathological changes and the ameliorative effects of melatonin in male rats. Fourty adult male Wistar rats divided into 4 groups of 10 animals each were used for this study. Rats in group I (S/oil) served as passive control and received the soya oil (2 ml/kg). Rats in group II (Mel) (active control) were administered with melatonin (0.5 mg/kg), while those in group III (CPF) were exposed to CPF only (8.5 mg/kg ~ 1/10th of the LD50). Rats in group IV (Mel + CPF) were pretreated with melatonin (0.5 mg/kg) and then exposed to CPF (8.5 mg/kg), 10 minutes later. The regimens were administered orally by gavage once daily for a period of 28 days. During this period, the rats were observed for signs of toxicity and death. At the end of the study period, the rats were sacrificed, and sera obtained from the blood samples of the animals were analyzed for testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), triiodothyronine (T3), thyroxine (T4) and thyroid stimulating hormone (TSH). Testicular tissues and pituitary glands were assayed for the levels of malonaldehyde (MDA), catalase (CAT) and superoxide dismutase (SOD) and acetylcholinesterase (AChE). Testicular weight, epididymal sperm count and semen characteristics were also evaluated. The sections of the brain, testes, adrenal glands, liver and kidneys were examined for histopathological changes. The results showed that pretreatment with melatonin ameliorated the CPF induced alterations in toxic signs, epididymal sperm count, semen characteristics, testicular weight, histopathological changes and levels of testosterone, FSH, LH, T3, T4, TSH, MDA, AChE, CAT and SOD. In conclusion, subacute CPF-induced alterations in sex hormones and semen characteristics were ameliorated by melatonin due to its antioxidant and AChE restoration properties. Therefore, it is conceivable
that farmers, pesticide applicators and individuals who are repeatedly exposed to low-dose CPF and perhaps, other organophosphates may be protected from the pesticide-evoked reproductive toxicity by pretreatment with melatonin.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF MASTER OF SCIENCE IN VETERINARY TOXICOLOGY DEPARTMENT OF VETERINARY PHYSIOLOGY AND PHARMACOLOGY, FACULTY OF VETERINARY MEDICINE, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
Keywords
AMELIORATIVE,, MELATONIN ON SUBACUTE CHLORPYRIFOS-INDUCE,, REPRODUCTIVE TOXICITY,, WISTAR RATS,