AimWe aimed to investigate the potential role of endothelin-1 (ET-1) in the regulation of the expression of -smooth muscle actin (-SMA) in human myometrial fibroblasts. MethodsPrimary myometrial fibroblasts were obtained from myometrium and were identified by immunocytochemical staining. Then, 1x10(7) cells were treated with ET-1 at a concentration of 0.1, 1.0, 10.0, or 100.0nM for 24h. To investigate the time course effects of ET-1 on the growth of fibroblasts, 1x10(7) cells were treated with 10.0nM ET-1 for 6, 12, 24, and 48h. Real-time quantitative PCR (qPCR) and Western blot analysis were used to determine the expression of -SMA mRNA and protein, respectively. ResultsHuman myometrial fibroblasts were identified by immunohistochemistry. Compared with the control group, the expression levels of -SMA mRNA and protein were identified in cells treated with ET-1 at a concentration of 0.1, 1.0, 10.0, or 100.0nM for 24h (P<0.05). ET-1 treatment affected the expression of -SMA mRNA and protein in a dose-dependent manner (P<0.05). The induction of -SMA mRNA and protein expression increased from 6 to 48h. ConclusionThe results show that ET-1 induces the expression of -SMA in human myometrium in vitro.