Effect of human muscle-derived stem cells on cryoinjured mouse bladder contractility

Objective: To investigate the effect of human muscle-derived stem cells (hMDSCs) on ameliorating impaired detrusor contractility in a cryoinjured bladder murine model. Methods: The hMDSCs were isolated and cultured by modified preplate technique, and only CD34-positive hMDSCs were extracted by Mini-MACS kits. Isolated hMDSCs were prelabeled with PKH26 and injected into the cryoinjured bladder to observe the pattern and characteristics. The nude mice were subdivided into three groups: normal group (N), cryoinjury bladder group with saline injection (C), and hMDSCs injection group after cryoinjury (M). At 2 weeks after injecting hMDSCs, we compared the contractility of bladder muscle strip stimulated by electrical field stimulation (EFS), acetylcholine (Ach.), and adenosine triphosphate (ATP), and the bladder smooth muscle tissue was examined by immunohistochemistry. Results: The contractile powers of bladder muscle strip in the C group were more decreased than the N group after EFS, Ach, and ATP treatment (P <.05). The bladder contractility of the M group was more increased than in the C group (P <.05), but was lower than the N group after EFS and Ach treatment. However, there was no significant difference of contractile power between the C and M groups after ATP stimulation. In immunohistochemical staining, the thickness of the bladder smooth muscle layer in the M group was significantly increased compared with the C group, and PKH26-labeled implanted cells were positive for smooth muscle cell differentiation marker (α-SMA) in the injected region. Conclusion: hMDSCs injection increased cholinergic bladder contractile power but not the purinergic component of bladder contraction after cryoinjury.