A Novel Method of Urinary Sphincter Deficiency: Serial Histopathology Evaluation in a Rat Model of Urinary Incontinence

Comparative study of two different rat models of stress urinary incontinence

INTRODUCTION AND HYPOTHESIS

The purpose of this study was to compare the success rate and urodynamic characteristics of the rat model of stress Urinary incontinence established by ovariectomy at different times after vaginal dilation.

METHODS

Eighty female rats were randomly divided into three groups: the control group (n = 20), model group A (n = 30), i.e., the animals received colpectasis and bilateral oophorectomy within 1 day; model group B (n = 30), i.e., the animals received bilateral oophorectomy 1 week after colpectasis. The sneeze test and urodynamics were tested.

RESULTS

There was no significant difference between the model group A and the model group B (p > 0.05) in the sneeze test. The leak point pressure (LPP) of model groups A and B was lower than that of the control group (p < 0.05). The LPP value of model group A was lower than that of model group B (p < 0.05). There was no significant difference in maximum bladder capacity (MBC) between model group A and the control group (p > 0.05); the MBC value of model group B was lower than that of the control group and model group A (p < 0.05).

CONCLUSIONS

Models of stress urinary incontinence in rats can be successfully established by both modeling methods. In terms of LPP, model groups A and B had lower values than the control group, and model group A had lower values than model group B. In terms of MBC, there was no difference between model group A and the control group, and model group B had lower values than the control group and model group A.

Application of adipose-derived, muscle-derived, and co-cultured stem cells for the treatment of stress urinary incontinence in rat models

OBJECTIVES

Based on the recent advancements in cell therapy techniques, we aimed to evaluate the efficacy of transurethral injection of autologous adipose-derived stem cells, muscle-derived stem cells, and co-cultured cells for the rehabilitation of stress urinary incontinence rat models. We hypothesized that the utilization of co-cultured stem cells could result in enhanced therapeutic outcomes attributed to their more comprehensive environment of paracrine factors and cytokines.

METHODS

We performed bilateral pudendal nerve transection surgeries to simulate urinary incontinence in 25 female Wistar rats and employed urodynamic evaluations to confirm the injury. We autologously isolated and cultured adipose-derived mesenchymal stem cells, muscle-derived stem cells, and a mixed culture of the two types, which we subsequently injected into the urethral lumen of the damaged animals. Three weeks after the injection, urodynamic assays, histological staining, and immunohistochemical evaluations were performed to determine the efficacy of the implanted cell cultures in sphincter function improvements or structural modifications.

RESULTS

Histological evaluations suggested a regenerative process in the muscular layer of the external sphincter 3 weeks after the injection. Also, immunohistochemical analysis revealed a thickened periurethral striated muscle layer in the co-cultured group. Postinjection urodynamic analysis indicated that the urethral pressure profile significantly increased in the co-cultured group compared with other groups.

CONCLUSIONS

The outcomes of this investigation indicated that the application of co-cultured adipose-derived and muscle-derived stem cells could be associated with higher therapeutic value in stress urinary incontinence patients compared with singular-cell treatments.