INTRODUCTION AND OBJECTIVES: Adipose derived stem cells(ADSC)are nonimmunogenic and have the ability to self-renew and to differentiate into multiple cell types.They has been used to restore urinary sphincter function in animal models.But there is not strong evidence regarding the role of the vehicle that must be used in combination with ADSC to improve effectiveness at the injection site.Objective: To assess whether adipose stem cell(ADSC)plus platelet rich plasma(PRP)could promote urethral sphincter restoration in a stress urinary incontinence(SUI)rat model.METHODS: Thirty five female inbred Wistar rats were used in our study.Animals were divided into seven groups(five animals per group): continent(C),sham(S),PNT(D),PNT+PBS injection(P),PNT+PBS+ADSC injection(PA),PNT+PRP injection(R)and PNT+PRP+ADSC injection(RA).Twenty five females rats underwent bilateral pudendal nerve section(PNT)to induce SUI.ADSCs were purified from fat tissue of a 4-week-old inbred male Wistar rat,labeled CM-Dil and injected into the urinary sphincter in twelve o(A) clock position with 70 microliltres of PBS or PRP.Four weeks after injection,cystometry was undertaken in all animals and leak point pressure(LPP)measured to assess urethral resistance function.All groups were sacrificed after cystometry,urethra sections were submitted for histology,immunohistochemistry assessment.RESULTS: LPP was increased significantly in R,RA and PA animals after implantation(P < 0.01),but was not different from group C and S.Histological and immunohistochemical examination demonstrated increased numbers of surviving ADSCs increased muscle/collagen ratio as well as increased microvessel density at the injection sites in RA compared to PA animals(CM-Dil+).CONCLUSIONS: PRP may potentially improve the action of transplanted ADSC to restore the histology and function of the urethral sphincter in a SUI rat model