Role of autophagy in reduction of high glucose and hypoxia-reoxygenation injury to isolated cardiomyocytes by dexmedetomidine in rats
10.3760/cma.j.cn131073.20200922.00227
- VernacularTitle:自噬在右美托咪定减轻大鼠高糖离体心肌细胞缺氧复氧损伤中的作用
- Author:
Zhongyu SHI
;
Yonghong XIONG
;
Bingyu LI
;
Zhongyuan XIA
- From:
Chinese Journal of Anesthesiology
2021;41(2):242-245
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To evaluate the role of autophagy in reduction of high glucose and hypoxia-reoxygenation (HG+ H/R) injury to isolated cardiomyocytes by dexmedetomidine in rats.Methods:The normally cultured rat H9c2 cardiomyocytes at the logarithmic growth phase were seeded in 6-well plates at a density of 1×10 6 cells/ml and divided into 4 groups ( n=15 each) using a random number table method: control group (group C), group HG+ H/R, dexmedetomidine group (group DEX) and dexmedetomidine+ autophagy inhibitor 3-methylpurine group (group 3-MA). The cells were incubated in culture medium with 1% fetal bovine serum + 1% double antibody for 24 h when the cell density reached 50%.To establish HG+ H/R injury model, the cardiomyocytes were cultured in high-glucose culture medium (glucose concentration of 33 mmol/L) for 24 h, and then incubated in a 37 ℃ incubator (95% N 2+ 5%CO 2) for 4 h followed by reoxygenation (90%O 2+ 10%CO 2) for 2 h. Dexmedetomidine was added until the final concentration reached 5 μmol/L at 1 h before hypoxia in DEX and 3-MA groups, and 3-MA was added until the final concentration reached 5 μmol/L at 1 h of incubation with dexmedetomidine.At 2 h after reoxygenation, the cell viability was recorded by the cell counting kit-8 assay, lactate dehydrogenase (LDH) activity was detected by LDH kit, the expression of autophagy-related protein LC3, P62 and Beclin-1 was detected by Western Blot, the ratio of LC3Ⅱ/LC3Ⅰwas calculated, and the expression of P62 and Beclin-1 mRNA was detected by real-time polymerase chain reaction. Results:Compared with group C, the cell viability was significantly decreased in HG+ H/R, DEX and 3-MA groups, LDH activity in the supernatant was increased and expression of P62 was decreased in HG+ H/R and 3-MA groups, ratio of LC3Ⅱ/LC3Ⅰwas decreased in group 3-MA, and the expression of Beclin-1 was down-regulated in group HG+ H/R ( P<0.05). Compared with HG+ H/R group, LDH activity in the supernatant was significantly decreased, expression of Beclin-1, P62 and its mRNA was up-regulated, and ratio of LC3Ⅱ/LC3Ⅰwas increased in DEX group, and LDH activity in the supernatant was increased in group 3-MA ( P<0.05). Compared with DEX group, cell viability were decreased, LDH activity in the supernatant was increased, Beclin-1, P62 and its mRNA was down-regulated, and ratio of LC3Ⅱ/ LC3Ⅰwas decreased in group 3-MA ( P<0.05). Conclusion:Autophagy is involved in the reduction of HG+ H/R injury to isolated cardiomyocytes by dexmedetomidine in rats.
