Dihydromyricetin alleviates pyroptosis and necroptosis in mice with MPTP-induced chronic Parkinson's disease by inducing autophagy

Abstract

To investigate the effect of 8-week dihydromyricetin (DHM) treatment on motor ability of mice with MPTP/probenecid-induced Parkinson's disease (PD) and explore the molecular mechanism. Sixty C57BL/6 mice were randomized into the control group, PD model group, PD+DHM group and PD+NEC-1 group (n=15). In the latter 3 groups, the mice were treated with 25 mg·kg-1·d-1 MPTP and 250 mg·kg-1·d-1 probenecid twice a week for 5 weeks to establish PD models; DHM (100 mg·kg-1·d-1) was administered 5 times a week via gavage for 8 weeks and NEC-1 (6.25 mg·kg-1·d-1, twice a week) via intraperitoneal injection for 5 weeks. The changes in motor function of the mice were assessed, and the expressions of TH, GFAP and Iba-1 in the substantia nigra were detected with immunofluorescence assay; serum levels of IL-1β and LDH were detected using ELISA. The mRNA expressions of TNF-α and IL-6 were determined with RT-PCR, and the expressions of TH and proteins associated with pyroptosis, neuroinflammation, necroptosis and autophagy in the striatum were detected using Western blotting. MPP +-activated Bv-2 cells were treated with different concentrations of DHM or 3-MA, and the expressions of proteins associated with autophagy and NLRP3 were detected using Western blotting; PI staining was used to detect cell necroptosis. The PD mouse models showed significantly reduced TH-positive cells and TH protein expression (P < 0.001). DHM obviously ameliorated motor deficits and TH loss in PD mice, increased TH expression (P=0.0023), decreased α-syn levels (P < 0.001), lowered the protein expressions of GFAP (P=0.045) and Iba-1 (P < 0.001) and the mRNA and protein levels of TNF-α (P=0.0015) and IL-6 (P < 0.001), and increased IL-4 level (P < 0.001). The 8-week DHM treatment significantly suppressed pyroptosis and necroptosis and activated autophagy in the striatum of the PD mice. In MPP +-induced Bv-2 cells, DHM treatment effectively reversed autophagy impairment and inhibited NLRP3 and TNF-α, IL-6 and IL-1β release, and the anti--inflammatory effects of DHM was obviously blunted by 3-MA. DHM can improve motor function of PD mice probably by activating autophagy to inhibit pyroptosis and necroptosis and reduce neuroinflammation.