102 Adipose-derived Stem Cells (ASCs) Combined with Control-released DF-PEG/GCS Hydrogel Scaffold Restore the Erectile Function in a Diabetes Rat Model

Abstract

To investigate the feasibility of seeding adipose-derived stem cells (ASCs) onto a control-released hydrogel scaffold, Telechelic difunctional poly/ Glycol chitosan (DF-PEG/GCS), and then inject the scaffold into corpus cavernosum for erectile function restoration in a diabetes mellitus erectile dysfunction rat model and investigate the underlying mechanism. Fourty-eight 8-week-old male Sprague-Dawley rats were randomly divided into 6 groups, including the Normal (n=8) group, PBS (n=8) group, ASCs (n=8) group, G+ASCs group (n=8), D+ASCs group (n=8) and H+ASCs group (n=8). For in vivo studies, rats with streptozocin-induced DM were intravenously injected with PBS, ASCs or ASCs seeded on GCS, DF-PEG or DF-PEG/GCS Hydrogel and rats in Normal group were injected with an equal volume of vehicle solution. Twelve weeks later, the intracavernosal pressure (ICP) and mean arterial pressure (MAP) were measured to assess erectile function, and penile tissues were harvested for further evaluation. A significant fall in the ICP was obvious in diabetic rats compared with normal rats. After rats with diabetes were treated with ASCs seeded DF-PEG/GCS Hydrogel, the ICP/MAP ratio significantly increased compared with that in the PBS group. Partial restoration of the ICP was observed in ASCs group. The CD31, a-SMA and NEUN expression levels were considerably decreased in the corpus cavernosum tissue of the PBS group compared with the Normal group (P < 0.05;). Twelve weeks after treatment with ASCs, expression levels of CD31, NEUN and a-SMA were significantly increased compared with those treated with PBS (P < 0.05). There was no significant difference between the G+ASCs, D+ASCs and ASCs groups. Western blot analysis was performed to determine the expression levels of bioactive factors NGF, BDNF and VEGF. Densitometric analysis of the band intensity revealed that in all cases, the decrease in expression of cell growth factors (NGF, BDNF and VEGF) as a result of diabetes in the rats was partially recovered by ASCs, and further restored by ASCs seeded DF-PEG/GCS hydrogel scaffold. Changes in expression of the inflammatory cytokines TNF-α, IL-6 and IL-1β in the penile tissue were investigated by real-time PCR. In all cases, the sharp increase in the expression of inflammatory factors in the diabetic rats compared with the normal rats, was attenuated by ASCs and further decreased by ASCs seeded hydrogel scaffold (P < 0.05 for TNF-α, IL-6 and IL-1β).