Immunomodulatory activities of polysaccharides from Chlorella pyrenoidosa in a mouse model of Parkinson's disease

•Polysaccharides from C. pyrenoidosa (CPS) reduced bradykinesia within the PD model.•CPS inhibits the inflammatory process in both central and peripheral system.•The gut immune biomarkers were enhanced by CPS treatment.•CPS may relieve the syndromes of PD by regulating the inflammation.•CPS delays PD progression via immunomodulatory action. Neuro-inflammation is implicated as a major pathogenic factor in Parkinson's disease (PD). Dietary supplements of Chlorella pyrenoidosa possess great anti-inflammatory activities, but its neuroprotective effect remains unclear. The aim of this study was to investigate the effects of polysaccharides from Chlorella pyrenoidosa (CPS) on motor activity, dopamine expressions, microglial activation, and peripheral immunomodulatory responses in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. The results of this study indicated that CPS reduced bradykinesia, inhibited the loss of striatal dopamine and its metabolites, and led to an increase in tyrosine hydroxylase in PD mice. In addition, CPS also suppressed the striatal Emr1 expression and tumor necrosis factor-α, interleukin-1β and IL-6 levels in serum. Furthermore, the gut immune biomarkers such as serum diamine oxidase and small intestinal secretory immunoglobulin A were enhanced by CPS treatment. These findings demonstrate that CPS has protective effect in MPTP-induced neurotoxicity in this model of PD via its immunomodulatory action.