Abstract: Objective To investigate the effect of miR-140-5p on retinopathy in diabetic rats through targeted regulation of high mobility group protein 1(HMGB1)/nuclear factor κB inhibitory protein-α(IκB-α) axis. Methods Diabetic rats were randomly divided into model group, miR-140-5p agomir group, agomir-NC group, and control group with 10 in each. Serum and retinal tissue were isolated, and the expression of miR-140-5p and HMGB1 mRNA in serum and retinal tissue was detected by RT-qPCR. HE staining was used to evaluate pathological changes. The level of serum monocyte chemoattractant protein-1(MCP-1), tumor necrosis factor-ɑ(TNF-ɑ) and intercellular adhesion molecule-1(ICAM-1) was detected by ELISA. Retinal cell apoptosis was examined by TUNEL staining. Dual luciferase reporter gene assay was used to detect the targeting relationship between miR-140-5p and HMGB1. The protein expressions of HMGB1, IκB-α and NF-κb p65 in retinal tissue were detected by Western blot. Results HMGB1 was the target gene of miR-140-5p. The content of MCP-1, TNF-ɑ, and ICAM-1, the expression of HMGB1 and NF-κB p65 , apoptotic cells counting and tissue damage in the model group and agomir-NC group were found to be all higher than those in the control group. The miR-140-5p agomir group was lower than that in the model group(P＜0.05). The expression of miR-140-5p and IκB-α in the model group and agomir-NC group were lower than those in the control group and the miR-140-5p agomir group was higher than that in the model group(P＜0.05). Conclusions Up-regulation of miR-140-5p may negatively regulate HMGB1 and improve the expression of IκB-α to alleviate retinopathy of diabetic rats.

Key words: miR-140-5p, diabetic retinopathy, HMGB1/IκB-α, apoptosis