Piperine Improves Experimental Autoimmune Encephalomyelitis (EAE) in Lewis Rats Through its Neuroprotective, Anti-inflammatory, and Antioxidant Effects.

Reza Nasrnezhad,Fereshteh Pourabdolhossein,Sohrab Halalkhor,Farzin Sadeghi

doi:10.1007/s12035-021-02497-5

Abstract

Inflammation, demyelination, glial activation, and oxidative damage are the most pathological hallmarks of multiple sclerosis (MS). Piperine, a main bioactive alkaloid of black pepper, possesses antioxidant, anti-inflammatory, and neuroprotective properties whose therapeutic potential has been less studied in the experimental autoimmune encephalomyelitis (EAE) models. In this study, the efficiency of piperine on progression of EAE model and myelin repair mechanisms was investigated. EAE was induced in female Lewis rats and piperine and its vehicle were daily administrated intraperitoneally from day 8 to 29 post immunization. We found that piperine alleviated neurological deficits and EAE disease progression. Luxol fast blue and H&E staining and immunostaining of lumbar spinal cord cross sections confirmed that piperine significantly reduced the extent of demyelination, inflammation, immune cell infiltration, microglia, and astrocyte activation. Gene expression analysis in lumbar spinal cord showed that piperine treatment decreased the level of pro-inflammatory cytokines (TNF-α, IL-1β) and iNOS and enhanced IL-10, Nrf2, HO-1, and MBP expressions. Piperine supplementation also enhanced the total antioxidant capacity (FRAP) and reduced the level of oxidative stress marker (MDA) in the CNS of EAE rats. Finally, we found that piperine has anti-apoptotic and neuroprotective effect in EAE through reducing caspase-3 (apoptosis marker) and enhancing BDNF and NeuN expressing cells. This study strongly indicates that piperine has a beneficial effect on the EAE progression and could be considered as a potential therapeutic target for MS treatment. Upcoming clinical trials will provide a deeper understanding of piperine's role for the treatment of the MS.

Highlights

Multiple sclerosis (MS) is the typical inflammatory demyelinating disease of the central nervous system (CNS) and a major cause of neurological disability in young adults worldwide [1]
Gene expression analysis in lumbar spinal cord showed that piperine treatment decreased the level of pro-inflammatory cytokines (TNF-α, IL-1β) and inducible nitric oxide synthase (iNOS) and enhanced IL-10, nuclear factor erythroid 2-related factor 2 (Nrf-2), HO-1and myelin basic protein (MBP) expressions
We found that piperine has anti-apoptotic and neuroprotective effect in EAE through reducing caspase-3 and enhancing BDNF and neuronal nuclear protein (NeuN) expressing cells

Summary

Introduction

Multiple sclerosis (MS) is the typical inflammatory demyelinating disease of the central nervous system (CNS) and a major cause of neurological disability in young adults worldwide [1]. Experimental autoimmune encephalomyelitis (EAE) is a Th-1 mediated inflammatory demyelinating disease of the CNS that best represents the pathology of MS [2, 3]. Inflammation, demyelination, gliosis (astrocytes and microglial activation), oligodendrocyte death and axonal loss are the most pathological hallmarks of MS and EAE [4, 5]. Glial activation is implicated in EAE and MS disease development and progression [6, 7]. The reactivated microglia and astrocytes release inflammatory factors such as tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-17, IL-6, and reactive oxygen species (ROS), which lead to the destruction of myelin, oligodendrocytes and axons in MS and EAE [8]. Oxidative stress and NO derived from inducible nitric oxide synthase (iNOS) is thought to play an important role in the pathobiology of EAE and MS diseases [10, 11]

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