Abstract

NEUROHISTOCHEMICAL ASSESSMENT OF WITHDRAWAL EFFECTS IN QUININE INDUCED TOXICITY ON THE MEDULLA OBLONGATA OF ADULT WISTAR RATS

Odubela Olukayode Olusola, Fakunle Ponle Bamidele*, Ehiremen Samuel Ehimare, Adeleye Ademola Stephen, Adelele Stephen Opeyemi, Adejinmi Suliat Opeyemi, Dawodu Adekunle Jonathan and Odeyemi Festus Ayotunde

ABSTRACT

Introduction: Neurotoxicity refers to the harmful impacts substances have on the nervous system. Quinine a drug commonly used in treatment of Chloroquine-resistant malaria is noted to have neurotoxic affinity on the central nervous system, including the medulla oblongata, a vital region of the brainstem responsible for crucial autonomic functions. Aim: To investigate the histochemistry of withdrawal effects of quinine induced toxicity on medulla oblongata of adult wistar rats. Method: Thirty (30) adult wistar rats, weighing between 200±50g, were randomly separated into three groups (n=10). The control group received distilled water only, Treated group (T1) received 25mg/kg bd.wt quinine (orally) for 4 weeks. Withdrawal group (T2) received 25mg/kg bd.wt quinine (orally) for 4 weeks and subjected to a quinine withdrawal period of 2 weeks. The animal were sacrificed exposure through cervical dislocation and the medulla oblongata was removed and process for histological analysis (H&E, Feulgen, Bielschowsky, Luxol Fast and Cresyl Violet) and biochemical assays for SOD, CAT and LDH was determined. Data obtained from the study were analyzed using one-way ANOVA and subjected to Graftpad Prism. Results: Revealed significant decrease in brain size of rats in both treated and withdrawal groups compared to control (P value < 0.0001). The levels of SOD, CAT and LDH activities decreased significantly relative to control (P value < 0.0001) with increased in the T2 group. Histological findings showed alterations in the histo-morphology of the medulla of treated (T1) group when compared to the control group, while the withdrawal (T2) group showed significant restorative changes compared to treated group. Conclusion: Quinine has neurotoxic effects on medulla oblongata but findings suggest that these effects of quinine are reversible and dose- dependent.

Keywords: Neurotoxicity, Quinine, Medulla Oblongata, Anti-oxidants.