NEUROBEHAVIOURAL AND HISTOMORPHOLOGICAL CHANGES IN THE HIPPOCAMPUS AND CEREBELLUM OF WISTAR RATS TREATED WITH ARTESUNATE AND AMODIAQUINE

Abstract

Artemisinin-based Combination Therapy (ACT) is among the best chemotherapeutic options for malaria. Artesunate (AS) + Amodiaquine (AQ) is a commonly used ACT in Nigeria, having good efficacy but with side effects involving memory loss and impaired motor coordination ranging from acute to chronic. Reports on acute effect of AS+AQ on the cerebellum and hippocampus are controversial and there is dearth ofinformation on its delayed effect on these brain areas. This study was designed to evaluate the effects of AS+AQ administration on neurobehaviour and morphology of the hippocampus and cerebellum in Wistar rat after three-day acute treatment. Eighty adult male Wistar rats (120±5g) were divided into 4 groups (n=20): Group A: Control (CT: Distilled water), Group B: AS (4mg/kg), Group C: AQ (10mg/kg) and Group D: AS (4mg/kg) + AQ (10mg/kg). Drugs were administered orally, once daily for 3 days and animals monitored for 14 days. Weights of the animals were recorded. Spatial memory and motor function were evaluated using Morris water-maze and fore limb grip tests, respectively. Animals were sacrificed by cervical dislocation on the 4 th and 15th day. Collected blood samples were analysed for full blood count. Excised cerebelli and hippocampi were processed for lipid peroxidation, biochemical markers of oxidative stress including nitric oxide (NO). Histological (Haematoxylin & Eosin) and immunohistochemical techniques including Glial Fibrillary Acid Protein (GFAP) and Cyclo-oxygenase II (COX-2) were also carried out. Data were analysed by ANOVA at α0.05. There was no significant variation in weight, neurobehavioural, haematological, biochemical, morphological and immunohistochemical parameters between all groups for the 3 days. At 14 days, AQ group had significant weight loss (30.40%) compared with the CT group and significantly increased swimming time (22.86±2.70s) compared with the CT group (4.14±0.74s). The AS (8.00±1.11s) and AQ (7.43±0.92s) had significantly decreased grip time compared with CT (17.86±1.22s); AQ significantly increased RBC (8.30±0.13/µL) and PCV (57.00±1.30%) compared with CT (RBC: 6.90±0.31/µL, PCV: 45.80±1.36%). Lipid peroxidation (per nmmol/g) increased significantly in AS (233.07±2.26), AQ (257.14±2.06) and AS+AQ (223.32±1.99) compared with CT (180.33±0.47). Ditto for NO (/µm/mg) (CT: 455.49±3.93, AS: 472.32±0.91, AQ: 525.74±10.11, AS+AQ: 480.95±2.917). The cerebellar Purkinje cell population was significantly reduced in the AS (2.50±0.29) and AQ (1.25±0.25) groups compared with CT (5.75±0.48), indicating pyknosis. Hippocampal Cornus Ammonis 1 cells were significantly depopulated in the AS (10.75 ±0.48) and AQ (7.25±0.48) groups compared to the CT (13.25±0.25) group, also indicating pyknosis. The GFAP expressions (per %area) significantly increased in the cerebelli of AS (55.95±1.85) and AQ (57.79±1.85) groups compared with CT (23.60±3.02) and in AS (76.81±7.19) and AQ (83.71±3.78) groups of hippocampus compared with CT (55.19±3.86), indicating astrogliosis. Compared with CT (59.36±5.61), AS (83.99±5.18) and AQ (88.32±0.88) had significantly increased hippocampal COX-2 expression per %area, indicating inflammation. Neurobehavioural and morphological changes due to Artesunate and Amodiaquine administration in Wistar rats were significant only after 14 days.