Abstract:

Objective To investigate the effects of Dendrobium huoshanense polysaccharide （DHP） on the levels of dopamine（DA） in striatum， levels of inflammatory factors and activities of antioxidant enzymes in substantia nigra tissue of the Parkinson’s disease（PD） mice induced by 1-methyl-4-phenyl-1，2，3，6-tetrahydropyridine（MPTP），and to elucidate the ameliorative effect of DHP on PD. Methods The C57BL/6J mice were randomly divided into control group，model group， and different doses（25， 50 and 100 mg·kg^－1） of DHP groups.Except for control group，the mice in other groups were used to establish the PD models by intraperitoneal injection of MPTP.The mice in different doses of DHP groups were given by gavage with different doses of DHP， and the mice in control and model groups were given the equal amount of saline by gavage. The behaviors of mice in various groups were examined by the method of turning sticks. The levels of DA in striatum of the mice in various groups were determined by high performance liquid chromatography（HPLC）； the levels of malondialdehyde（MDA） and the activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） in substantia nigra tissue of the mice in various groups were determined by chemical colorimetry.The levels of interleukin-1β （IL-1β） and tumor necrosis factor-α （TNF-α） in substantia nigra tissue of the mice in various groups were determined by enzyme linked immunosorbent assay（ELISA）. Results Compared with control group， the drop latency of the mice in model group was significantly shortened（P<0.05）； compared with model group， the drop latencies of the mice in 50 and 100 mg·kg^－1 DHP groups were significantly prolonged （P<0.05）. Compared with control group， the level of DA in striatum of the mice in model group was significantly decreased （P<0.05）；compared with model group， the levels of DA in the striatum of the mice in 50 and 100 mg·kg^－1 DHP groups were significantly increased （P<0.05）. Compared with control group， the level of MDA in substantia nigra of the mice in model group was significantly increased （P<0.05）， and the activities of SOD and GSH-Px were significantly decreased （P<0.05）；compared with model group，the levels of MDA in substantia nigra of the mice in 50 and 100 mg·kg^－1 DHP groups were significantly decreased（P<0.05），and the activities of SOD and GSH-Px in substantia nigra of the mice were significantly increased（P<0.05）. Compared with control group， the levels of IL-1β and TNF-α in substantia nigra tissue of the mice in model group were significantly increased （P<0.05）；compared with model group， the levels of IL-1β and TNF-α in substantia nigra tissue of the mice in 50 and 100 mg·kg^－1 DHP groups were significantly decreased （P<0.05）. Conclusion DHP has a certain protective effect on nerve function in the MPTP-induced PD mice， and its mechanism may be related to inhibition of oxidative damage and reduction of neuroinflammatory response.

Key words: Parkinson’s disease, Dendrobium huoshanense polysaccharide, Oxidative stress, Neuroinflammatory factor