Effects of short-term severe and long-term mild STZ-induced diabetes in urethral tissue of female rats.

Aims: To estimate and compare the alterations in the urethral tissues of female rats with two diabetes models: short-term severe and long-term mild diabetes.

Methods: To induce mild diabetes (blood glucose levels between 120 and 300 mg/dl), female newborns received streptozotocin (100 mg/kg body weight, sc route), and to induce short-term severe diabetes (blood glucose levels > 300 mg/d), adult animals received streptozotocin (40 mg/kg, iv route). The rats were killed on day 133 of the experimental via an i.p. Thiopentax injection of 80 mg/kg, and the urethrovaginal tissues were harvested. Morphometric, pathological, immunohistochemical, and ultrastructural analyses were conducted.

Results: In the long-term mild diabetes group, collagen deposition, severe fibrosis, lipid droplets and numerous subsarcolemmal, and intermyofibrillar mitochondria were observed. In the short-term severe diabetes group, centrally located myonuclei and a significantly reduced striated muscle area were noted. Both diabetic models exhibited similar immunohistochemistry patterns, with changes from fast to slow fibers and a decrease in the numbers of fast fibers.

Conclusions: Either long-term mild hyperglycemia or short-term severe hyperglycemia have detrimental impacts on muscle health. They are both involved in the failure to maintain healthy skeletal muscle that may contribute to the development of pelvic floor dysfunctions via different pathways. These results have important implications for monitoring and prevention strategies for improving the quality of life of women with diabetes mellitus and pelvic floor muscle dysfunction. Neurourol. Urodynam. 36:574-579, 2017. © 2016 Wiley Periodicals, Inc.