Neuroprotective effects of α-melanocyte-stimulating hormone against the neurotoxicity of 1-methyl-4-phenylpyridinium.

Parkinson's disease (PD) is the second most common neurodegenerative disease in humans. The hormone α-melanocyte-stimulating hormone (α-MSH) has been reported to be neuroprotective in previous studies. The aim of this study is to investigate the neuroprotective effects of α-MSH against the neurotoxicity of 1-methyl-4-phenylpyridinium (MPP+). Our results indicated that treatment with α-MSH in M17 cells attenuated MPP+-induced oxidative stress, embodied by exacerbated reactive oxygen species and protein carbonyls. In addition, we found that α-MSH could improve mitochondrial function in M17 cells through increasing the level of adenosine triphosphate and mitochondrial membrane potential. Furthermore, treatment with α-MSH restored the reduction of cell viability and the induction of lactate dehydrogenase release induced by α-MSH. Importantly, Hoechst staining results indicated that α-MSH treatment significantly reduces the number of apoptotic cells after treatment with MPP+. Mechanically, we found that α-MSH prevented apoptosis signals through reducing the level of cleaved caspase-3 and attenuating cytochrome c release. All these data imply that α-MSH produces a protective effect in PD.