AB159. BDNF-hyper secreting human umbilical cord blood mesenchymal stem cells promote erectile function in a rat model of cavernous nerve electrocautery injury

INTRODUCTION: Erectile dysfunction (ED) continues to be a significant problem for men following radical prostatectomy. AIM: To test the hypothesis that intracavernous injection of BDNF-hyper secreting human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) can ameliorate ED in a rat model of cavernous nerve electrocautery injury (CNEI). METHODS: Forty-two male Sprague-Dawley rats were randomly divided into four groups. Group A: sham operation rats intracavernosally injected with PBS (n=6); group B: CNEI rats intracavernosally injected with PBS (n=12); group C: CNEI rats intracavernosally injected with hUCB-MSCs (n=12); group D: CNEI rats intracavernosally injected with BDNF-hUCB-MSCs (n=12). MAIN OUTCOME MEASURES: At week 4, the rats in each group underwent electrostimulation of the cavernous nerves to assess erectile function. Penile tissues were collected for histological examinations (Masson’s trichrome; immunofluorescence for S-100 and α-SMA; TUNEL assay). Transmission electron microscopy (TEM) was used to examine the CN distal to the site of injury. RESULTS: Four weeks after injection, rats which received BDNF-hUCB-MSCs showed the most significant improvement in the ratio of maximal ICP to MAP (ICP/MAP) compared with both the CNEI + hUCB-MSCs and CNEI + PBS animals (P<0.001). Histological examinations showed moderate recovery of S-100 positive nerve fibers, ratio of smooth muscle to collagen and smooth muscle content in the CNEI + hUCB-MSCs group and remarkable recovery in the CNEI + BDNF-hUCB-MSCs group compared to the CNEI + PBS group (P<0.05). Furthermore, there was a significant reduction of apoptotic index in the corpus cavernosum of the CNEI + hUCB-MSCs and CNEI + BDNF-hUCB-MSCs rats compared with the CNEI + PBS animals (P<0.05). By TEM examination, atrophy of myelinated and nonmyelinated nerve fibers was noted in CNEI+PBS group, and significant recovery was observed in two treated groups. CONCLUSIONS: Intracavernous injection of BDNF-hyper secreting hUCB-MSCs can enhance the recovery of erectile function, promote the CNs regeneration, protect against cells apoptosis and inhibit corpus cavernosum fibrosis after CNEI in a rat model.