Role of microRNA-29a in the development of diabetic retinopathy by targeting AGT gene in a rat model

Abstract

Objectives: This study intends to explore the role of microRNA-29a (miRNA-29a) in the development of diabetic retinopathy by targeting AGT gene in a rat model.

Methods: Fifty-six DR rat models were established and divided into 7 groups (with 8 rats in each group): the model group, the miRNA-29a group, the miRNA-29a knockdown group, the negative control (NC) group, the AGT group, the miRNA-29a+AGT group, and the miRNA-29a knockdown+AGT group respectively, while 8 normal rats were selected as the normal group. The qRT-PCR was used to detect the expression of miRNA-29a and AGT mRNA. The AGT protein expression was measured using Western blotting. The ADPase histochemical staining was applied to detect retinal neo-vascular morphology. The number of retinal vascular endothelial cells was counted by H&E staining.

Results: MiRNA-29a and AGT mRNA expressions were negatively correlated. Compared with rats in the normal group, the miRNA-29a expression in DR rats of each group decreased, but the AGT mRNA and protein expression increased; the vascular distribution was in disorder, and the new retinal vessels, vascular density, and endothelial nuclei all increased. Compared with the model group, miRNA-29a increased, and the AGT mRNA and protein expression decreased in the miRNA-29a group; additionally, the vascular density, tortuosity, and endothelial cell nuclei significantly decreased. The opposite trend was found in the miRNA-29a knockdown group, the miRNA-29a knockdown+AGT group, and the AGT group, particularly in the miRNA-29a knockdown+AGT group.

Conclusion: Overexpression of miRNA-29a could down-regulate AGT expression, thereby preventing the development of DR in a rat model.

Keywords: Angiotensinogen; Diabetic retinopathy; Endothelial cell nucleus; MicroRNA-29a; Rat model; Retinal neovascularization; Vascular density.