Abstract:

Objective·To investigate the effects of glucose reperfusion after low-glucose on the activity of autophagy in rat cardiomyocyte H9c2. Methods·H9c2 cells were assigned to low glucose group (LG), glucose reperfusion group (RG), autophagy inhibition group (RG+CQ), and control group (Con). LG group was treated with low glucose medium for 2 h. RG group was treated with high glucose medium for 2 h after being treated with low glucose medium for 2 h. For RG+CQ group, CQ was added 1 h before low glucose and high glucose treatment. Con group was treated with high glucose medium. MTT assay was used to detect the proliferation of H9c2 cells, lactate dehydrogenase assay was used to detect the cytotoxicity, and Western blotting was used to measure the expressions of p-mTOR, mTOR, p-AMPK, AMPK LC3, and beclin-1. Results·RG group had reduced cell proliferation capacity and increased LDH activity as compared with LG group (P<0.05). RG+CQ group had lower cell proliferation capacity and higher LDH activity as compared with RG group (P<0.05). Results of Western blotting showed that RG group had higher expressions of p-AMPK, LC3II/I, and beclin-1 and lower expression of p-mTOR as compared with LG group (P<0.05), and RG+CQ group had higher expression of LC3II/I and beclin-1 as compared with RG group (P<0.05). Conclusion·Glucose reperfusion after low-glucose increases autophagy activity in H9c2 cells. This may be related to the activation of AMPK/mTOR pathway and increased autophagy activity can protect cardiomyocytes.

Key words: low-glucose, glucose reperfusion, H9c2 cell, autophagy, AMPK/mTOR