METHODS: Cell counting kit 8(CCK-8)was used to detect the cell viability of human retinal epithelial cells ARPE-19 stimulated with 5, 15, 45, 135mmol/L HG. The ARPE-19 cells were divided into NC group, 45mmol/L HG group, si-NC+45mmol/L HG group, si-lncRNA KCNQ1OT1+45mmol/L HG group, miR-NC+45mmol/L HG group, miR-19a-3p mimics+45mmol/L HG group, si-con+45mmol/L HG group, si-TSHZ3+45mmol/L HG group, pcDNA+si-lncRNA KCNQ1OT1+45mmol/L HG group, pcDNA-TSHZ3+si-lncRNA KCNQ1OT1+45mmol/L HG group. CCK-8 was used to detect cell viability, qRT-PCR was used to detect the expressions of lncRNA KCNQ1OT1, miR-19a-3p and TSHZ3 mRNA, Western Blot was used to detect TSHZ3, activation-cysteine-containing aspartate proteolytic enzyme 3(Cleaved-caspase-3), B-cell lymphoma/leukemia-2(Bcl-2)related X protein(Bax)protein expressions, and enzyme-linked immunosorbent assay(ELISA)was used to detect the levels of oxidative stress indicators reactive oxygen species(ROS)and malondialdehyde(MDA). The dual luciferase activity was used to detect the targeted binding between lncRNA KCNQ1OT1 and miR-19a-3p, miR-19a-3p and TSHZ3.

RESULTS: 15, 45, 135mmol/L HG inhibited the survival rate of ARPE-19 cells, and the subsequent select the HG concentration 45mmol/L with a cell survival rate of about 50%. 45mmol/L HG increased the expression levels of lncRNA KCNQ1OT1, TSHZ3 mRNA, TSHZ3 protein, the apoptosis rate, Cleaved-caspase-3 and Bax protein expressions, ROS and MDA levels in ARPE-19 cells, and reduced cell survival rate and the expression level of miR-19a-3p(P<0.05). Low expression of lncRNA KCNQ1OT1, TSHZ3 or high expression of miR-19a-3p improved the survival rate of ARPE-19 cells induced by HG, and reduced apoptosis rate, Cleaved-caspase-3 and Bax protein expressions, ROS and MDA levels(P<0.05). lncRNA KCNQ1OT1 targeted miR-19a-3p, miR-19a-3p targeted TSHZ3, and lncRNA KCNQ1OT13 regulated the expression of TSHZ3 through miR-19a-3p. The effect of lncRNA KCNQ1OT1 low expression on the survival rate, apoptosis and oxidative stress of ARPE-19 cells induced by HG was reversed by the overexpression of TSHZ3.

CONCLUSION: The low expression of lncRNA KCNQ1OT13 promotes the proliferation of retinal epithelial cells induced by high glucose, and inhibits their apoptosis and oxidative stress through miR-19a-3p/TSHZ3.