ABSTRACT.We investigated the effect of microRNA-27b (miR-27b), a gene expression regulatory factor, on the expression of monocyte chemoattractant protein-1 (MCP1) stimulated by interleukin 17 (IL-17). After IL-17 had been added to H9C2 cardiomyocytes, an miR27b mimic was transfected into the H9C2 cells. The mRNA expression levels of miR-27b and MCP1 in the H9C2 cells were detected by SYBR green I fluorescence quantitative reverse transcription polymerase chain reaction. Enzyme-linked immunosorbent assay was used to measure the expression levels of MCP1 protein in the H9C2 cells. The expression of MCP1 mRNA in the H9C2 cells began to increase 2 h after IL-17 stimulation, reached a peak at 4 h, and then decreased. The MCP1 protein level increased gradually in the 24 h following IL-17 stimulation. After transfection with the miR-27b mimic, the expression of miR-27b in the H9C2 cells significantly increased than that in the miRNA negative control group (P < 0.01). The MCP1 mRNA and protein levels in the miR-27b mimic + IL-17 group were significantly reduced than that in the miRNA negative control + IL-17 group (P < 0.01). miR-27b inhibited IL-17-induced MCP1 expression in the H9C2

ABSTRACT. Diabetic retinopathy (DR), an important complication of diabetes mellitus (DM), is not well understood. T helper cell balance (Th1/Th2) is involved in various autoimmune diseases; however, its role in DR is not understood. This study explores changes in Th1 and Th2 cytokine expression during DR. Blood samples were collected from 25 healthy volunteers (normal control group), 35 patients with type 2 DM (T2DM group) without DR, and 30 cases of T2DM patients with DR (DR group). Real-time PCR was used to measure mRNA expression of IL-2 and TNF-α, secreted from Th1 cells, and of IL-4 and IL-10, secreted from Th2 cells. We used ELISA to detect cytokine expression in serum to analyze the correlation between Th1 and Th2 cytokines. IL-2 and TNF-α mRNA and protein expression levels in the T2DM and DR groups were significantly higher than in the normal control group (P < 0.05). Compared with the T2DM group, the DR group had higher IL-2 and TNF-α levels (P < 0.05). IL-4 and IL-10 levels were lower in the DR group compared with the normal and T2DM groups (P < 0.05), while T2DM showed no difference compared with the normal control (P > 0.05). IL-2 and TNF-α were negatively correlated with IL-4 and IL-10 in the DR group, respectively. We found that Th1 cytokine secretion was higher and Th2 cytokines secretion was lower during DR, leading to a Th1/ Th2 imbalance, suggesting that Th1/Th2 imbalance is a side effect for DR occurrence and development.