Heliang Liu

Protective Effects of Inosine on Urinary Bladder Function in Rats With Partial Bladder Outlet Obstruction

OBJECTIVES To evaluate the protective effects of inosine on bladder dysfunction, nerve density, and oxidative damage after partial bladder outlet obstruction in rats. METHODS A total of 60 adult male Sprague-Dawley rats were divided into 5 groups. Groups 1-4 underwent bladder outlet obstruction. Groups 1-3 were treated with inosine at 100, 150, or 225 mg/kg/d intraperitoneally and group 4 with saline. Group 5 consisted of sham-operated control rats. At 21 days postoperatively, cystometry were performed in 30 rats (6 per group). In the remaining 30 rats (6 per group), the bladders were excised and used for contractile responses to various stimulations, immunohistochemical examination for protein gene product 9.5 (a neuronal marker) and evaluation of superoxide dismutase activity and thiobarbituric acid reductase substance level. RESULTS Inosine administration resulted in dose-dependent protective effects on the contractile responses to both field stimulation and carbachol, although the protective responses to KCl was restricted to a greater dose of inosine. A dose-dependent reduction in residual volume was noted in inosine-treated groups at different dosages compared with the saline-treated group. In addition, the protein gene product 9.5-positive nerve density decreased in the saline-treated group but significantly increased in the inosine-treated (225 mg/kg/d) group. Compared with the saline-treated group, significantly enhanced superoxide dismutase activity and a reduced thiobarbituric acid reductase substance level were observed in the inosine-treated group at 150 and 225 mg/kg/d. CONCLUSIONS These results suggest that inosine has a potential protective effect against partial bladder outlet obstruction-induced bladder dysfunction and oxidative injury in rats.

Urethral Reconstruction with Tissue-Engineered Human Amniotic Scaffold in Rabbit Urethral Injury Models

Background Mitigating urethral injury remains a great challenge for urologists due to lack of ideal biomaterials for urethroplasty. The application of amniotic membrane (AM) over other synthetic materials makes it a better potential source for urethral reconstruction. We separated the basement layer of AM to obtain denuded human amniotic scaffold (dHAS) and then inoculated primary rabbit urethral epithelial cells on the surface of dHAS to determine whether this strategy minimizes potential rejection and maximizes the biocompatibility of human AM. Material/Methods After the successful acquisition of dHAS from AM, cell-seeded dHAS were prepared and characterized. Both cell-seeded dHAS and acellular dHAS were subcutaneously implanted. Immune responses were compared by histological evaluation and CD4+ cell and CD8+ cell infiltrations. Then they were applied as urethroplastic materials in the rabbit models of urethral injury to fully explore the feasibility and efficacy of tissue-engineered dHAS xenografts in urethral substitution application. Results Mild inflammatory infiltration was observed in cell-seeded dHAS grafts, as revealed by fewer accumulations of CD4+ cells and CD8+ cells (or neutrophils or other immune cells). Urethral defects of rabbits in the urethroplastic group with dHAS implantation (n=6) were completely resolved in 1 month, while there were 1 infection and 1 fistula in the control group with acellular dHAS patches (n=6). Histopathological analysis revealed mild immune response in the cell-seeded dHAS group (P<0.05). Conclusions Tissue-engineered dHAS minimizes potential rejection and maximizes the biocompatibility of AM, which makes it a potential ideal xenograft for urethral reconstruction.