Neuroprotective effect of centella asiatica leaves extract on substantia Nigra neurons -a quantitative study in mice

Abstract

Centella asiatica is a small medicinal herb, growing in damp soil. In Ayurvedic medicine, Centella asiatica is used extensively as brain tonic to enhance learning and memory power. In the present study, the neuroprotective role of Centella asiatica (CeA) leaf extract on substantia nigra neurons against stress induced neurodegeneration in mice was investigated. Mice were divided into four groups and treated as follows: (i) Normal control (NC) - remained undisturbed in the cage, (ii) Saline control (SC) - treated with saline, (iii) Stressed group (S) – remained in the restrainer for 6 hours/day for 6 weeks, (iv) Stress + Centella asiatica treated group (S+CeA) - stressed and received orally CeA leaf extract throughout the stress period (n=6 in all groups). After 6 weeks, brain was removed and processed for Golgi staining. Substantia nigra neurons were traced using camera lucida focused at 400X magnification. The concentric circle method of Sholl was used to quantify the dendrites. The results showed less number of dendritic branching points and dendritic intersections in stressed group. On the other hand, the number of dendritic branching points and dendritic intersections of substantia nigra neurons in group (iv) were significantly more. The results conclude that, oral intubation of centella asiatica leaves extract increased dendritic branching points and dendritic intersections of substantia nigra neurons. Keywords: Restraint stress, Substantia nigra, Dendritic branching points, Dendritic intersections