Ficus exasperata vahl improves manganese-induced neurotoxicity and motor dysfunction in mice

Abstract

Manganese is an important element in the biological system, however, excessive exposure may lead to a neurological disorder known as manganism. The present study sought to investigate the ameliorative effects of Ficus exasperata Vahl (E.Vahl) on motor function and neuronal integrity of the Substantia nigra (SNc) and Corpus striatum (CPu) after acute exposure to manganese. Fifty adult male Balb/c mice weighing between 25 – 35g were divided into 5 groups – Group A (normal saline), Group B (Manganese), Group C (E.Vahl), Group D (Post-treatment), Group E (concurrent treatment). Manganese was intraperitoneally administered at 40mg/kg b.w, while E.Vahl orally at 200 mg/kg b.w. Motor coordination was assessed in the animals using Rotarod and Parallel Bar tests. Animals were later sacrificed; brain tissue extracted and processed for histology/immunohistochemistry. Manganese-exposed group showed decreased motor activity on the Rotarod test. Decreased motor activity shown by the increase in latency of turn (LoF) was recorded in the Parallel Bar test. Manganese induced activation of microglia and astrocytic cells in the SNc and CPu, which plays an important role in neurodegeneration as observed in the reduction of TH cells. Indistinct Nissl granules were also noticed in the manganese-exposed group. Treatment with E.Vahl produced significant motor improvement, as well as ameliorative effect on the histoarchitecture of the SNc and CPu. The present investigation has demonstrated the motor-enhancing and neuro-restorative potential of E.Vahl after manganese exposure in adult mice.

Key Word: Neurodegeneration; Manganism; Ficus exasperata; Rotarod; immunohistochemistry.