The effect of human muscle-derived stem cells (MDSC) and glycine-boleucine-lysine-valine-alanine-valine (GIKVAV) on the cryo-injured bladder of nude mouse

Abstract

Purpose: In neurogenic bladder, both smooth muscle contraction and nerve regeneration are very important for functional improvement. Glycine-isoleucine- lysine-valine-alanine-valine (GIKVAV) is a peptide that can induce nerve regeneration in vivo. In this study, we evaluated bladder function after injection of muscle-derived stem cells (MDSCs) and GIKVAV into the cryo-injured bladder of nude mice. Materials and Methods: Human muscle samples were obtained from the rectus abdominis muscle of 12 patients who underwent laparotomy. The purpose and entire method of the study were explained to the patients, and all subjects who participated in this study provided written informed consent. The MDSCs were isolated by a modified preplate technique, and only CD34+ human MDSC were extracted by use of Mini-MACS kits. The nude mice were subdivided into 5 groups (n=40): normal group (N, n=8), saline injection group after cryo-injury (S, n=8), GIKVAV injection group after cryo-injury (G, n=8), human MDSC injection group after cryo-injury (M, n=8), and GIKVAV and human MDSC injection group after cryo-injury (GM, n=8). At 2 weeks after injection, we compared the contractility of a bladder muscle strip of each group by organ bath and polygraph by using electronic field stimulation (EFS). Nerve regeneration was evaluated by choline acetyl transferase (ChAT) immunostaining. Results: The contractile powers of the N, S, G, M, and GM groups were 3.58±0.27, 1.54±0.25, 1.54±0.31, 2.49±0.36, and 2.44±0.34 mN/mg, respectively, by EFS. The contractility of the bladder muscle strip in the S and G groups was lower than that in the N group. The contractile powers of the M and GM groups were lower than those of the N group but greater than those of the S and G groups. In ChAT immunohistochemical staining, nerve regeneration was increased in the G and GM groups compared with the S and M groups. Conclusions: Nerve regeneration was induced by GIKVAV injection regardless of human MDSC injection. There was no direct effect of GIKVAV on bladder muscle contractility. ？ The Korean Urological Association, 2009.