Piperine pre-treatment has immunomodulatory effects in hippocampal local model of demyelination

Introduction: Inflammatory processes has an important role in the Multiple Sclerosis (MS)’s pathophysiology. Therefore, hampering the inflammatory factors could be an effective strategy in MS treatment. Piperine (the main alkaloid of black piper) has immunomodulatory and anti-inflammatory properties. In this study the pre-treatment effects of piperine on the gene expression level of inflammatory and anti-inflammatory cytokines, growth factors and myelin repair was investigated. Materials and Methods: Adult male Wistar rats (200–250 g) in 4 experimental groups (1: Control, 2: LPC, 3: LPC+vehicle, 4: LPC+PP 5) were studied (n=8). The pre-treatment with piperine (5 mg/kg) started 2 weeks before demyelination induction by bilateral injection of lysolecithin into the CA1 regions of the hippocampus, until the end of experiment. Myelin repair process was analyzed with myelin specific staining. The evaluation of astrocyte activation was done by immunohistochemistry and the gene expression analysis for IL-1β, TNF-α, NF-kB, FOXP3, IL-10, BDNF and NGF in the hippocampal tissue was done by Real-time PCR technique. Results: Pre-treatment with piperine significantly decreased the extent of demyelination and increased myelin optical density. Moreover, glial activation and expression level of inflammatory cytokines (IL-1β, TNF-α, NF-kB) were significantly decreased in the pre-treatment groups with piperine and the level of anti-inflammatory cytokines (FOXP3, IL-10) increased in the hippocampal tissue. The increased expression level of BDNF and NGF was also observed in the piperine pre-treated group. Conclusion: Piperine improved myelin repair process through reduction of inflammatory cytokines, glial activation and enhancement of anti-inflammatory cytokines and growth factors