Expression Of Smoothelin In Diabetic Cystopathy Of The STZ-induced Guinea Pigs

Objective To investigate the expression of Smoothelin in urinary bladder of streptozotocin-induced diabetic guinea pigs and the possible mechanisms of diabetic cystopathy.Methods Fifty female guinea pigs were randomly divided into STZ-induced diabetic (42) and normal control (8). Urodynamic study was to evaluate the changes of bladder functionand and distinguish the diabetic cystopathy group among others. Immunohistochemistry and Western blot were used to detect the alteration of the expression of Smoothelin in diabetic bladder of guinea pigs within9and12weeks. Imrnunoreactivity of different bladder tissues also were observed. The expression amounts of Smoothelin were standardized by beta-actin.Results Being detected by urodynamic of18successful STZ-induced diabetic models, the bladder capacity and residual urine were augmented, but the detrusor leak point pressure was increased in compensated stage(16.57±0.48cmH2O) and then decreased significantly in decompensated stage(6.46±0.51cmH2O) of diabetic guinea pigs(DCP) while the pressure of the controls was regarded as normal (15.29±1.38cmH20).With the same changes, the expression intensity and levels of Smoothelin were rose early and reduced lately in diabetic animals while compared with age-matched normal controls. Furthermore, according to the results of immunohistochemisty, immunostaining of muscularis mucosa in compensated and decompensated groups were weaker than the controls whereas the presentations of blood vessels were similar in three different groups. In contrast to the Smoothelin expressional level of the controls(3.755±0.128), the Smoothelin efficiency was significantly up-regulated in compensated group (4.585±0.0502) but decreased sharply in decompensated group (1.730±0.183). on the other hand, compared to the clearly changes of Smoothelin expression, the expression level of beta-actin were not different among these groups.Conclusions Smoothelin is clearly related to myogenic dysfunction of diabetic cystopathy with the contribution for the contractility of detrusor and useful to distinguish the transition from compensated to decompensated state. In particular, Smoothelin may play a important role at the modulation of SMC phenotypes. Maintaining contractile phenotypes of detrusor SMCs would be a useful pathway to prevent and treat the disease of diabetic cystopathy.