Induced differentiation of adipose-derived stromal cells into myoblasts

This study aimed to induce the differentiation of isolated and purified adipose-derived stromal cells (ADSCs) into myoblasts, which may provide a new strategy for tissue engineering in patients with stress urinary incontinence (SUI). ADSCs, isolated and cultured ex vivo, were identified by flow cytometry and induced to differentiate into myoblasts in the presence of an induction solution consisting of DMEM supplemented with 5-azacytidine (5-aza), 5% FBS, and 5% horse serum. Cellular morphology was observed under an inverted microscope. Ultrastructural changes occurring during the differentiation were observed by transmission electron microscopy and confocal laser scanning microscopy. Cellular immunohistochemical staining was applied to determine the expression of desmin protein in cells with and without induced differentiation. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to detect mRNA and protein expression, respectively, of sarcomeric and desmin smooth muscle proteins. The results showed that ADSCs were mainly of a spindle or polygon shape. Flow cytometry analysis revealed that ADSCs did not express CD34, CD45, and CD106 but high levels of CD44 and CD90, which confirmed that the cultured cells were indeed ADSCs. After induction with a 5-aza-containing solution, morphological changes in ADSCs, including irregular cell size, were observed. Cells gradually changed from long spindles to polygons and star-shaped cells with microvilli on the cell surface. Many organelles were observed and the cytoplasm was found to contain many mitochondria, rough endoplasmic reticulum (rER), and myofilament-like structures. Cell immunohistochemical staining revealed different levels of desmin expression in each phase of the induction process, with the highest expression level found on day 28 of induction. RT-PCR and Western blot results confirmed significantly higher desmin gene expression in induced cells compared with control cells, but no significant difference between the two groups of cells in sarcomeric protein expression. It was concluded that under specific induction setting, ADSCs can be induced to differentiate into myoblasts, providing a potential new option in stem cell transplantation therapy for SUI.