Effect of alprostadil on myocardial fibrosis in rats with diabetes mellitus via TGF-β1/Smad signaling pathway.

Abstract

To observe the influence of alprostadil on myocardial fibrosis in rats with diabetes mellitus (DM) through the transforming growth factor beta-1 (TGF-β1)/Smad signaling pathway. Wistar rats were employed to induce models of DM (DM group), and alprostadil treatment group (ALPR group) and control group (NC group) were set up. After successful modeling, blood and myocardial tissues were collected from rats. Next, blood glucose level, liver function, and myocardial function were detected. In addition, hematoxylin-eosin (HE) assay was performed to determine pathological changes. The enzyme-linked immunosorbent assay (ELISA) was carried out to measure serum interleukin-6 (IL-6) and cardiac function indexes such as ejection fraction (EF), Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Western blotting, which were applied to measure the gene and protein expression levels of important molecules in the proliferation and differentiation of myocardial fibroblasts [including checkpoint kinase 1 (Chek1) and alpha-smooth muscle actin (α-SMA)] and the relevant pathway TGF-β1/Smad2. The blood glucose level was increased in DM group (p<0.01), suggesting that modeling is successful. The tumor necrosis factor-alpha (TNF-α), IL⁃6, and IL-1 levels were higher in DM group than in NC group. DM group had significantly elevated serum content of alkaline phosphatase (ALP), alanine aminotransferase (ALT), and creatine kinase (CK), as well as left ventricular end-diastolic dimension (LVEDd) and left ventricular end-systolic dimension (LVESd), but it clearly decreased fractional shortening (FS) and EF in comparison with NC group. Besides, myocardial cells were orderly arranged in NC group, while myocardial fibrosis was observed in DM group. The results of RT-PCR showed that the levels of Collagen, Chek1, α-SMA, TGF-β1, and Smad2 in myocardial fibroblasts were notably lowered in ALPR group, but evidently increased in DM group (p<0.05). According to Western blotting, there were evident decreases in the levels of TGF-β1 and Smad2 in myocardial fibroblasts in ALPR group (p<0.05). The above results suggest that alprostadil represses the expression of the TGF-β1/Smad2 signaling pathway and its relevant molecules, thus further suppressing the fibrosis of myocardial cells. Alprostadil treats myocardial fibrosis in DM rats by inhibiting the TGF-β1/Smad2 signaling pathway.