Carica Papaya Leaf Crude-extract Ameliorates Lipopolysaccharide-induced Neurotoxicity in Mice Cerebellum by Downregulating GFAP and IBA-1 Expression

This study assessed the ameliorative role of Carica papaya leaf crude extract (CPLCE) in lipopolysaccharide (LPS) model of neurotoxicity in mice. Thirty-two adult male mice (25 - 30g) were randomly assigned to three groups (A & C; n=8, B; n= 16 i.e. B1 and B2). B1 was treated with LPS once/daily for seven days. B2 was initially treated with LPS once/day for 7 days, followed by treatment with CPLCE once daily for the last seven days. Groups A and C received distilled water and CPLCE respectively for the duration of the experiment. During the treatment, physical clinical signs were monitored for in the mice and a neurobehavioral test (wire hanging test) was carried out to ascertain muscle strength. The mice’s brains were harvested and their cerebellum excised. Immunostaining for GFAP and Iba1 was performed using standard procedures as well standard H& E technique. Results from this study suggest significant cerebellar degeneration in group B1 treated with LPS only when compared to groups A & C. There was a marked recovery of the degenerating cerebellar cytoarchitecture in group B (B2) when treated with CP for the next 7days when compared to those treated with LPS only. This was further confirmed by reduced expression of cerebellar GFAP and Iba-1 in this group. The absence of cerebellar degeneration and normal expression of GFAP and Iba-1 was observed in group C treated with CP only for 14 days. In conclusion, CP could prove to be promising for possible neuroinflammatory diseases treatment.

Key Words: Neuroglia, Immunohistochemistry, Acute neurotoxicity, Cerebellum, Neurodegenerative changes.