Role of Notch1/Hes1 signaling pathway in high glucose and hypoxia-reoxygenation injury to cardiomyocytes / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of Notch1/hairy and enhancer of split homolog1(Hes1) signaling pathway in high glucose and hypoxia-reoxygenation (H/R) injury to cardiomyocytes.Methods:H9c2 cardiomyocytes were cultured in low-glucose DMEM culture medium supplemented with 10% fetal bovine serum.The cells were divided into 6 groups ( n=12 each) using a random number table method: control group (group C), H/R group, H/R+ Jagged-1 group (group H/R+ J), high glucose group (group HG), high glucose+ H/R group (group HG+ H/R) and high glucose+ H/R+ Jagged-1 group (group HG+ H/R+ J). The cells were incubated in low-glucose culture medium for 72 h in group C. After incubated in low-glucose culture medium for 72 h, the cells were exposed to 24-h hypoxia in an incubator filled with 95% N 2-5% CO 2 at 37℃, immediately followed by 6-h reoxygenation in an incubator filled with 95% O 2-5% CO 2 at 37℃ in group H/R.In group H/R+ J, Jagged-1 (Notch1/Hes1 signaling pathway specific activator) 5μg/ml was added to low-glucose culture medium and the cells were incubated for 72h before H/R.In group HG, H9c2 cardiomyocytes were incubated in high-glucose culture medium containing 33 mmol/L glucose for 72 h. In group HG+ H/R, the cells were incubated in high-glucose medium for 72 h before H/R.In group HG+ H/R+ J, Jagged-1 5μg/ml was added to high-glucose culture medium, and the cells were incubated for 72 h before H/R.At 6 h of reoxygenation, the supernatant of the culture medium was collected for detection of the activities of superoxide dismutase (SOD) and lactic dehydrogenase (LDH), the cell viability (by CCK-8 assay) and the cell apoptosis rate (by flow cytometry) and for determination of expression of Notch1, Hes1 and c-caspase-3 (by Western blot). Results:Compared with group C, the cell survival rate and SOD activity were significantly decreased, and apoptosis rate and LDH activity were increased in H/R, H/R+ J and HG groups, expression of Notch1, Hes1 and c-caspase-3 was up-regulated in H/R and H/R+ J groups, and the expression of Notch1 and Hes1 was down-regulated and c-caspase-3 expression was up-regulated in group HG ( P<0.05). Compared with group H/R, the cell survival rate and SOD activity was significantly increased, apoptosis rate and LDH activity were decreased, expression of Notch1 and Hes1 was up-regulated, and c-caspase-3 expression was down-regulated in group H/R+ J, and the cell survival rate and SOD activity were significantly decreased, apoptosis rate and LDH activity were increased, expression of Notch1 and Hes1 was down-regulated, and c-caspase-3 expression was up-regulated in group HG+ H/R ( P<0.05). Compared with group HG, the cell survival rate and SOD activity were significantly decreased, and apoptosis rate and LDH activity were increased in HG+ H/R and HG+ H/R+ J groups ( P<0.05), and expression of Notch1 and Hes1 was down-regulated, and c-caspase-3 expression was up-regulated in group HG+ H/R ( P<0.05). Compared with group HG+ H/R, the cell survival rate and SOD activity were significantly increased, apoptosis rate and LDH activity were decreased, expression of Notch1 and Hes1 was up-regulated, and c-caspase-3 expression was down-regulated in group HG+ H/R+ J ( P<0.05). Compared with group H/R+ J, the cell survival rate and SOD activity were significantly decreased, apoptosis rate and LDH activity were increased, expression of Notch1 and Hes1 was down-regulated, and c-caspase-3 expression was up-regulated in group HG+ H/R+ J ( P<0.05). Conclusion:Activation of Notch1/Hes1 signaling pathway is the endogenous protective mechanism of high glucose and H/R injury to cardiomyocytes.