Effect of SIRT3 overexpression on hypoxia-reoxygenation injury to hippocampal neurons of mice exposed to high glucose: relationship with SOD2 / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of sirtuin 3 (SIRT3) overexpression on hypoxia-reoxygenation (H/R) injury to hippocampal neurons of mice exposed to high glucose and its relationship with SOD2.Methods:The normally cultured HT22 neurons at the logarithmic phase were selected and divided into 3 groups ( n=12 each) using a random number table method: high-glucose normoxia group (HG group), high glucose+ H/R group (HHR group) and high glucose+ H/R+ SIRT3 overexpression group (HHR+ SIRT3 group). To establish high glucose model, the neurons in 3 groups were cultured in high-glucose culture medium (glucose concentration of 50 mmol/L) for 8 h. In HHR and HHR+ SIRT3 groups, the cells were exposed to glucose-free and hypoxia for 6 h and then cultured in the high-glucose normoxic environment for 24 h to establish the high glucose and HR injury model.In HHR+ SIRT3 group, the neurons were transfected with SIRT3 overexpressed lentivirus.The cell viability was recorded by the cell counting kit-8 assay, reactive oxygen species (ROS) content was detected by flow cytometry, mitochondrial malonaldehyde (MDA) content, superoxide dismutase (SOD) activity, catalase (CAT) activity and adenosine triphosphate (ATP) content were determined by colorimetry, mitochondrial membrane potential (MMP) was detected by JC-1 probe, and the expression of nuclear respiratory factor 1 (NRF1), mitochondrial transcription factor A (TFAM), SIRT3, SOD2 and acetylated SOD2 (ac-SOD2) was detected by Western blot. Results:Compared with HG group, cell viability, SOD activity, CAT activity, ATP content, MMP, NRF1 and the expression of TFAM and SIRT3 were significantly decreased, and ROS content, MDA content and ac-SOD2/SOD2 ratio were increased in group HHR and group HHR+ SIRT3 ( P<0.05). Compared with HHR group, cell viability, SOD activity, CAT activity, ATP content, MMP, NRF1 and the expression of TFAM and SIRT3 were significantly increased, and ROS content, MDA content and ac-SOD2 /SOD2 ratio were decreased in HHR+ SIRT3 group ( P<0.05). Conclusion:SIRT3 overexpression can alleviate hypoxia-reoxygenation (H/R) injury to hippocampal neurons of mice incubated in high glucose medium, and the mechanism is related to activation of SOD2 deacetylation.