Pro‐apoptotic effects of micro‐ribonucleic acid‐365 on retinal neurons by targeting insulin‐like growth factor‐1 in diabetic rats: An in vivo and in vitro study

AIMS/OBJECTIVE: The present study aimed to explore the effects of micro‐ribonucleic acid‐365 (miR‐365) on apoptosis of retinal neurons by targeting insulin‐like growth factor‐1 (IGF‐1) in diabetes mellitus rats. MATERIALS AND METHODS: High glucose‐induced retinal neurons were assigned into the blank (with no plasmid transfection), negative control (with plasmid transfection), anti‐miR‐365 (transfected miR‐365 antagomir), transfected IGF‐1 short hairpin RNA plasmid (sh‐IGF‐1) and transfected miR‐365 antagomir and IGF‐1 shRNA plasmid (anti‐miR‐365 + sh‐IGF‐1) groups. Proliferation and apoptosis of retinal neurons were detected by 5‐ethynyl‐2′‐deoxyuridine assay and Hoechst 33342 staining, respectively. Expressions of miR‐365, IGF‐1, Bcl‐2‐associated X protein (Bax) and Bcl‐2 were determined by reverse transcription quantitative polymerase chain reaction and western blotting. A control group contained 10 healthy rats. Terminal deoxynucleotidyl transferase dUTP nick‐end labeling staining was used to evaluate apoptosis of retinal neurons in rats. RESULTS: In the anti‐miR‐365 group, the apoptosis rate and Bax expression were reduced in comparison with the negative control and blank groups, whereas the sh‐IGF‐1 and anti‐miR‐365 + sh‐IGF‐1 groups presented an opposite trend. Compared with the normal group, expressions of miR‐365 and Bax were increased, and expressions of IGF‐1 and Bcl‐2 were decreased, with more apoptotic cells in diabetes mellitus rat models. The sh‐IGF‐1 group had lower Bax expression, and higher expressions of IGF‐1 and Bcl‐2 with fewer apoptotic cells. Additionally, Bax expression was upregulated, expressions of IGF‐1 and Bcl‐2 were downregulated, and apoptotic cells were higher in the anti‐miR‐365 + sh‐IGF‐1 groups than the anti‐miR‐365 group. CONCLUSION: The results of the present study suggest that suppressed miR‐365 increases the IGF‐1 expression, leading to anti‐apoptotic effects on retinal neurons in diabetic rats.