Neuroprotective effects of ghrelin in cuprizone-induced rat model of multiple sclerosis

Multiple sclerosis (MS) is an inflammatory central nervous system disease characterized by demyelination and axonal loss and is the main cause of non-traumatic neurological disability in young adults. Although there are several treatment approaches to manage the disease, there is no definitive cure for multiple sclerosis. Inflammation and oxidative stress are known to play important roles in the pathophysiology of MS. Ghrelin, a peptide secreted by the stomach, is reported to have neuroprotective properties through several pathways, including attenuating oxidative stress and inflammation. In the present study cuprizone (CPZ)-induced model of MS was used in Wistar albino rats to study the possible anti-inflammatory, antioxidant and neuroprotective effects of ghrelin. Rats were randomly divided into six groups: Control groups (Control₃₅ and Control-S₄₂), demyelination group, remyelination group, remyelination + ghrelin (20 µg/kg) group and remyelination + ghrelin (40 µg/kg) group. Y maze test was performed on the rats on their last day of the experiment. Oxidative stress and inflammatory parameters were investigated in brain using commercial kits by enzyme-linked immunosorbent assay (ELISA). Luxol fast blue (LFB) and hematoxylen&eosin (H&E) staining were performed in brain tissues. CPZ leads to a significant decrease in glutathione peroxidase (GSH-Px) levels and myelin content and a significant increase in malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-ɑ), interleukin- 6 (IL- 6) levels, the number of lymphatic cells and inflammatory cells. A significant increase in the antioxidant parameter levels and a significant decrease in MDA levels were found in the ghrelin treated groups (p < 0.05). CPZ leads to irregular, fragmented, demyelinating nerve fibers. A more significant remyelination was observed in the ghrelin treated groups compared to the other groups (p < 0.05). In conclusion, ghrelin treatment showed neuroprotective and antioxidant properties and reduced demyelination in the CPZ-induced rat model of multiple sclerosis.