Periprostatic Implantation of Human Bone Marrow-derived Mesenchymal Stem Cells Potentiates Recovery of Erectile Function by Intracavernosal Injection in a Rat Model of Cavernous Nerve Injury

Objective To evaluate whether periprostatic implantation (PPI) of human bone marrow-derived mesenchymal stem cells (hBMSCs) potentiates recovery of erectile function after intracavernosal injection (ICI) of hBMSCs in a rat model of cavernous nerve (CN) injury. Methods Sprague-Dawley rats that had undergone bilateral CN injury were treated by ICI with or without PPI of hBMSCs (10 rats per group). hBMSCs were harvested from healthy human donors. Fibrin scaffolds were used for PPI of hBMSCs. After 4 weeks, erectile responses to electric pelvic ganglion stimulation were studied. The expression of neuronal nitric oxide synthase (nNOS)-positive nerve fibers and smooth muscle/collagen ratio was evaluated in each penis. Results ICI of hBMSCs slightly improved erectile function compared with the control group (maximal intracavernosal pressure/mean arterial pressure, 39.1% vs 21.7%; P = .060), but a combination of PPI and ICI significantly improved erectile function (45.0%, P = .007). After stem cell therapy, the number of nNOS-positive nerve fibers increased significantly in the PPI + ICI group ( P = .017). The smooth muscle/collagen ratio increased significantly after stem cell therapy in the ICI and PPI + ICI groups (both P