Dihydromyricetin improves Parkinson's disease-like lesions in T2DM rats by activating AMPK/ULK1 pathway / 生理学报

The purpose of this study was to explore the effect and mechanism of dihydromyricetin (DHM) on Parkinson's disease (PD)-like lesions in type 2 diabetes mellitus (T2DM) rats. The T2DM model was established by feeding Sprague Dawley (SD) rats with high-fat diet and intraperitoneal injection of streptozocin (STZ). The rats were intragastrically administered with DHM (125 or 250 mg/kg per day) for 24 weeks. The motor ability of the rats was measured by balance beam experiment, the changes of dopaminergic (DA) neurons and the expression of autophagy initiation related protein ULK1 in the midbrains of the rats were detected by immunohistochemistry, and the protein expression levels of α-synuclein (α-syn), tyrosine hydroxylase (TH), as well as AMPK activation level, in the midbrains of the rats were detected by Western blot. The results showed that, compared with normal control, the rats with long-term T2DM exhibited motor dysfunction, increased α-syn aggregation, down-regulated TH protein expression, decreased number of DA neurons, declined activation level of AMPK, and significantly down-regulated ULK1 expression in the midbrain. DHM (250 mg/kg per day) treatment for 24 weeks significantly improved the above PD-like lesions, increased AMPK activity, and up-regulated ULK1 protein expression in T2DM rats. These results suggest that DHM may improve PD-like lesions in T2DM rats by activating AMPK/ULK1 pathway.

DHM improves cognitive dysfunction in T2DM rats by inhibiting hippocampal endoplasmic reticulum stress / 中国药理学通报

Aim To investigate the effeet of dihydro- myricetin ( DHM ) on cognitive dysfunction in type 2 diabetes mellitus ( T2DM) rats and its mechanism.Methods SD rats were randomly divided into the normal control group ( n = 56) : normal diet and citrate buffer solution (30 mg • kg 1 ) ; T2DM model group (n =60) : high glucose, fat and low dose STZ ( 30 mg • kg 1 ) ( Four unsuccessful rats were eliminated ).Then rats in the above two groups were treated with or without DHM (250 mg • kg 1 • d intragastric).After 12 weeks, eight rats in each group were randomly selected to perform Morris water maze and Y maze test to observe the effect of DHM on cognitive function of rats.The remaining rats in each group were injected ERS antagonist tauroursodeoxycholic acid ( TUDCA ) 10 jxg • d 1 or ERS activator tunicamycin (TUN) 10 jxL, respectively.After the behavioral analysis, the hippocampal tissues of rats were taken out.The expressions of EH stress related proteins GRP78 and P- PERK were detected by Western blot.Results Both DHM and TUDCA could improve cognitive dysfunction in T2DM rats.On the contrary, TIJN reduced the effect of DHM on cognitive dysfunction in T2DM rats.TUDCA decreased the expression of GRP78 and p- PERK proteins in T2DM rats, while TUN increased the expression of GRP78 and p-PERK proteins in T2DM rats treated by DHM.Conclusion DHM improves cognitive dysfunction in T2DM rats, and the mechanism may be related to the inhibition of endoplasmic reticulum stress.