Genipin Protects High Glucose-injured MIN6 Cells / 中国生物化学与分子生物学报

ABSTRACT

Genipin (Gen) is an important antioxidant that plays a crucial role in the process of intracellular resistance to oxidative stress. In order to study the effect of genipin on MIN6 cells injured by high glucose, the CCK-8 method was used to detect the cell survival rate. The cell viability of the high-glucose injury group decreased (P <0. 05). But after genipin acted on the cells injured by high glucose, the cell viability increased (P <0. 05). The mouse insulin detection kit and ATP content detection kit found that the insulin release in the high glucose injury group decreased (P < 0. 001) and the ATP content decreased (P <0. 001). After genipin was given, the insulin release increased (P <0. 01), ATP content increased (P <0. 01). The fluorescent probe DCFH-DA detected the intracellular reactive oxygen species (ROS) level and found that the ROS content in the high glucose-injury group was significantly increased (P <0. 01). After genipin was administered, ROS content decreased (P < 0. 05). Glutathione(GSH) / oxidized glutathione (GSSG), intracellular malondialdehyde (MDA), superoxide dismutase(SOD) and catalase (CAT) and lactate dehydrogenase (LDH) activity in the cell supernatant revealed that the GSH / GSSH ratio, SOD and CAT levels in the high glucose injury group decreased (P <0. 05), and the intracellular MDA and LDH levels were significant increased (P<0. 001) .After administration of genipin, the GSH / GSSH ratio, SOD and CAT levels increased (P <0. 01), MDA and LDH levels were significantly reduced (P <0. 01). Mitochondrial membrane potential (MMP) levels decreased in the highglucose injury group (P <0. 01). After genipin acted on the cells injured by high glucose, the MMP level increased (P < 0. 05). Western blot detected uncoupling protein 2 (UCP2), antioxidative proteinsglutathione reductase (GR) and glutaredoxin 1 (Grx1) contents. The results showed that UCP2 contents in the high glucose injury group increased (P <0. 01) and the content of oxidized protein decreased (P < 0. 01). After genipin was administered, the expression of UCP2 decreased (P < 0. 05), and the expression of antioxidative protein increased (P < 0. 05). Experiments suggest that genipin has anantioxidant protective effect on MIN6 cells damaged by high glucose and maintains the function of MIN6cells to promote insulin secretion. This experiment provides experimental data for the antioxidation of genipin on MIN6 cells injured by high glucose, and also provides new ideas for the follow-up study of genipin in the treatment and prevention of diabetes.