OBJECTIVETo study the feasibility of inducing the differentiation of rat adipose-derived stem cells (ADSCs) into smooth-muscle-like cells in monolayer culture in vitro.

METHODSADSCs were obtained from the adipose of the inguinal region of the SD rat. A growth curve of the ADSCs was drawn. The fourth passage ADSCs were induced to differentiate into adipocytes with adipogenic inducing fluid and determined by Oil Red O staining, into osteoblasts with osteogenic inducing fluid and determined by Von Kossa staining, as well as into smooth-muscle-like cells with inducing fluid containing beta-mercaptoethanol, and the expression of alpha-smooth muscle actin (alpha-SMA) was detected by the immunohistochemical method.

RESULTSThe ADSCs presented spindle and polygon shapes and proliferated rapidly in vitro. The growth curve showed the ADSCs in the logarithmic growth phase two days after subculture. The fourth passage ADSCs exhibited red stained lipid droplets characteristic of adipocytes in the cytoplasm on Oil Red O staining after induction with adipogenic inducing fluid, and calcium nodes on Von Kossa staining after induction with osteogenic inducing fluid. The immunohistochemical results of the ADSCs induced into smooth-muscle-like cells showed that the positive rate of alpha-SMA in the beta-mercaptoethanol induced cells was (29.80 +/- 6.89)%, significantly higher than in the uninduced ones ([2.89 +/- 1.24]%, P < 0.01).

CONCLUSIONADSCs displayed obvious characteristics of smooth muscle cells after induction, and could be a new source of cells in the tissue engineering studies of smooth muscle related diseases.