Role of long non-coding RNA MEG3 in hyperglycose-induced neurocyte damage in rats: relationship with mitochondrion-dependent apoptosis

Abstract

Objective To evaluate the role of long non-coding RNA maternally expressed gene 3 (MEG3) in hyperglycose-induced neurocyte damage and the relationship with mitochondrion-dependent apoptosis in rats. Methods Normally cultured PC12 cells were divided into 5 groups (n=18 each) using a random number table method: normal concentration of glucose control group (C group), normal concentration of glucose plus MEG3 group (C+ MEG3 group), high-concentration glucose group (HG group), high-concentration glucose plus MEG3 group(HG+ MEG3 group), and high-concentration glucose plus negative lentiviral vector (LV-NC) group (HG+ NC group). PC12 cells were cultured in DMEM medium with 25 mmol/L glucose in group C. PC12 cells were cultured in DMEM medium with 25 mmol/L glucose after being transfected with MEG3 lentiviral vector (LV-MEG3) in C+ MEG3 group.PC12 cells were cultured in DMEM medium with 250 mmol/L glucose in HG group.PC12 cells were incubated in DMEM medium containing 250 mmol/L glucose after being transfected with LV-MEG3 in HG+ MEG3 group.PC12 cells were incubated in DMEM medium containing 250 mmol/L glucose after being transfected with LV-NC in HG+ NC group.After the cells were cultured or incubated for 1 day, the cell viability was measured by CCK8 assay, the apoptosis rate and level of reactive oxygen species (ROS) were determined by flow cytometry, and the amount of lactic dehydrogenase (LDH) released was measured by DCFH-DA, the expression of Cyt c, caspase-3, caspase-9, Bcl-2, Bax and Apaf-1 was determined by Western blot, and the opening of mitochondrial permeability transition pore (mPTP) was determined by fluorescent method.Blc-2/Bax ratio was calculated. Results Compared with group C, the cell viability was significantly decreased, the amount of LDH released, ROS level and apoptosis rate were increased, the opening of mPTP was increased, and the expression of caspase-3, caspase-9, Cyt c, Bax, Bcl-2 and Apaf-1 was up-regulated in HG, HG+ MEG3 and HG+ NC groups, and Bcl-2/Bax ratio was increased in HG+ MEG3 group and decreased in HG and HG+ NC groups (P<0.05). Compared with HG group and HG+ NC group, the cell activity was significantly increased, the amount of LDH released, ROS level and apoptosis rate were decreased, the opening of mPTP was decreased, the expression of caspase-3, caspase-9, Cyt c, Bax, and Apaf-1 was down-regulated, the expression of Bcl-2 was up-regulated, and Bcl-2/Bax ratio was increased in HG+ MEG3 group (P<0.01). Conclusion MEG3 may be involved in the endogenous protective mechanism during hyperglycose-induced neurocyte damage by inhibiting mitochondrion-dependent apoptosis in rats. Key words: RNA, long noncoding; Diabetes mellitus; Neurons; Apoptosis