EFFECT OF ETHANOL ON CEREBRAL AND CEREBELLAR CORTICES, NEUROBEHAVIOUR AND TRACE ELEMENTS OF NEONATAL WISTAR RATS AFTER INTRAUTERINE EXPOSURE

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Department of Medicine

ABSTRACT
Alcohol is the most widely used and abused psychoactive drug globally. Ethanol is the main ingredient in the three classes of alcoholic beverages. Children of alcoholic pregnant women are prone to wide spectrum of disorder referred to as Foetal Alcoholic Spectrum Disorder (FASD). The present study aimed at evaluating the teratologic effects of ethanol on the histology, neurobehaviour and trace elements of cerebellar and cerebral cortices of the neonatal Wistar rats. Twenty eight (28) female Wistar rats were mated with matured males in ratio 2:1. Pregnant dams were then grouped into 7. Group A served as the control group that received distilled water, Groups B, C and D were administered 0.5ml 20% ethanol for 7, 14 and 20 days during pregnancy respectively. Groups E, F and G were given 0.5ml 30% ethanol in the above stated manner. Following parturition, morphometric indices of the litters were taken at birth. Neuro behavioural assessments were done on postnatal days 5, 6 and 7. Cerebral and Cerebellar tissues were obtained and processed for paraffin embedding for histological evaluation using Haematoxylin and Eosin and histochemical study using Cresyl Fast Violet Stains. Atomic Absorption Spectrophotometry was used to quantify Iron, Zinc, Copper and Manganese in the cerebrum and cerebellum. The result showed effects on the weight and crown rump length of the pups by exhibiting lower weight and crown rump length values in the ethanol treated neonates. Intrauterine ethanol exposure was shown to affect the development of vestibular and postural reflexes, sensory and motor coordination with significance at p?0.05.Histological evaluation of the cerebral cortex revealed histopathological presentations such as pyknosis, karyorhexis, clumping of cells and neural degeneration. Histology of the cerebellar cortex showed degeneration and disorientation of purkinje cells. Histochemical evaluation of the cerebral cortex showed degradation of nissl substance. Moreover, the histochemistry of the cerebellar xvi cortex demonstrated chromatolysis of the purkinje cells.The concentration of Iron in cerebrum was depleted when compared with the control, there was no statistical significance at P?0.05, while the amount of Iron in the cerebellum was significantly elevatedin the treated groups (P?0.01, P?0.001). The amount of Copper in the cerebrum was also depleted while significantly elevated in the cerebellum (P?0.05). The concentration of Manganese in the cerebrum and the cerebellum was elevated in some of the treated groups and depleted in some of the treated groups as well, there was no statistical significance at P?0.05. The amount of Zinc in the cerebrum was depleted with high statistical significance (P?0.001) in all the ethanol-treated groups when compared with the control group. On the other hand, the concentration of Zinc in the cerebellum was also depleted but there was no statistical significance (P?0.05). The findings from this study revealed that, intrauterine ethanol exposure has potency of inducing teratogenicity on the morphometry, neuro-behaviour, histology, and alters the trace element concentrations in the brain of the neonates irrespective of the trimester equivalence.