Early ghrelin intervention protects against the progressive dopaminergic neuron loss in Parkinson’s disease mice
Abstract BackgroundGhrelin has been identified as a multifunctional peptide that has many potential applications for the treatment of various diseases, including Parkinson’s disease (PD). However, little is known about the pathophysiological function and mechanism of ghrelin in PD. MethodELISA was used for detecting plasma total and active ghrelin levels, dopamine (DA) content was measured by HPLC-ECD, immunofluorescence staining and Western blot were used to detect protein expressions, and cytokine was tested by Bio-PlexPro™ assay.ResultsHere, we reported a PD model that overexpressing mutant human A53T α-syn mice exhibited a decreased levels of total and active ghrelin in plasma, fewer tyrosine hydroxylase (TH)-positive neurons in the substantia nigra (SN), lower DA content in the striatum (Str), and less weight. These changes were rescued by the subcutaneous administration of low-dose ghrelin. Interestingly, ghrelin had no effect on weight gain in wild-type mice but improved weight loss in A53T mice. In addition, ghrelin administration also attenuated the decreased Bcl-2/Bax ratio and superoxide dismutase1 (SOD1) protein levels and inhibited the upregulation pro-inflammatory cytokine interleukin-6 (IL-6) and tumour necrosis factor a (TNFa) and the downregulation of anti-inflammatory cytokine IL-10. In addition, ghrelin inhibited the increase in Iba1-positive cells in mice with PD.ConclusionsHere we reported that ghrelin had a protective effect on dopaminergic neurons and against weight loss from PD via anti-oxidant, anti-inflammatory and anti-apoptotic mechanisms, which suggested that ghrelin could be an endogenous protective factor that prevents the onset or the progression of PD.