| Objective: To investigate the effects of tissue inhibitor of metalloproteinase-1 small interfering RNA(TIMP-1 si RNA)transfected fibroblasts(FB)for tissue-engineered urethral reconstruction in a rabbit model.Materials and Methods: Small intestinal submucosa(SIS)was prepared and the structure of scaffold was assessed using scanning electron microscopy.Rabbit oral keratinocytes(OK)and FB were isolated,expanded and TIMP-1 si RNA was transfected into FB.Enzyme linked immunosorbent assay(ELISA)was used for the evaluation of the secretion of type I collagen after TIMP-1 si RNA transfected into FB.OK and TIMP-1 si RNA transfected FB were seeded onto SIS.In 24 male rabbits,a ventral urethral mucosal defect with a mean length of2.0×0.8 cm was created.Urethroplasty was performed with SIS with no cell seeding(8rabbits,group 1),with OK-seeded SIS(8 rabbits,group 2)and with OK and TIMP-1 si RNA transfected FB-seeded SIS(8 rabbits,group 3).An 8Fr silicone catheter was inserted into the urethra after operation.At 1 and 6 months post-operatively,retrograde urethrogram and histologic analysis were performed to evaluate the outcomes of urethroplasty.Results: ELISA results showed that type I collagen concentration curve in transfected cells was lower than the blank control groups.Under retrograde urethrography,5 rabbits in group 1,6 in group 2 and 7 in group 3 maintained a wide urethral caliber.Histologically,the retrieved urethra in group 1 showed fibrosis and inflammation at 6 months.However,fibrosis and inflammation were mild in group 2 and group 3.Furthermore,the speed of urothelium,smooth muscle and vessel regeneration in group 3 was faster than that in group 2.Conclusion: Transfecting TIMP-1 si RNA into FB might inhibit the expression of TIMP-1,and may reduce the deposition of type I collagen.TIMP-1 si RNA transfected FB could prevent the proliferation of urethral scar tissue and could be used as a source of seed cell for urethral tissue engineering. |
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