Regulatory T cells in the pathogenesis of type 2 diabetes mellitus retinopathy by miR-155.

To explore the regulatory T cells (Treg) in the peripheral blood of diabetic retinopathy patients by microRNA-155 (miR-155), and investigate the mechanisms of regulatory T cells and miR-155 in the pathogenesis of diabetic retinopathy.The study explores the percentage of CD4+ CD25+ Foxp3+ T cells (Treg cells) and the expression of miR-155 in the peripheral blood of 20 cases with background diabetic retinopathy (BDR group) and 20 cases with proliferative diabetic retinopathy (PDR group). Flow cytometry and RT-PCR determined 18 cases with non-diabetic retinopathy (NDR group) and 20 cases of healthy control (NC group). ELISA determined the expression of TGF-β.The percentages of Treg cells in the peripheral blood of patients in BDR group, PDR group, and NDR group had significantly decreased compared to that in the NC group (p < 0.05). The percentages of the Treg cells in the BDR and PDR groups were lower than those in NDR group (p < 0.05 in both cases). The percentage of Treg cells in the PDR group was lower than that in the BDR group (p < 0.05). The expression levels of miR-155 in the peripheral blood of the patients in the BDR group, PDR group, and NDR group had significantly increased compared to that in NC group (p < 0.05). The expression levels of miR-155 in the BDR group and PDR group were higher than that in the NDR group (p < 0.05 in both cases). The expression level of miR-155 in the PDR group was higher than that in the BDR group (p < 0.05). The expression levels of TGF-β in the BDR group and PDR group were significantly decreased compared to those in the NDR group and NC group (p < 0.05 in both cases). The expression of miR-155 was negatively related to the Treg cells and the expression level of TGF-β2 (r1 = -0.835, p1 = 0.000, r2 = -0.771, p2 = 0.000).In type 2 diabetes mellitus (T2DM) retinopathy, miR-155 may play an important role in the pathogenesis of T2DM retinopathy by regulating the Treg cells with TGF-β.