A Correlational Study Between NGF And The Development Diabetic Cystopathy

Objective:This experiment establish diabetic rat model to study the urodynamic characteristics and bladder microscopic changes in the structure of the diabetic cystopathy (DCP), dynamically study the relationship between NGF (nerve growth factor) and the development of the DCP, provides a laboratory theoretical basis of new methods of treatment.Methods:65male SD rats were randomly divided into2groups, the control group(30) and diabetic group(35). Give the diabetic rat model group rats60mg/kg intraperitoneal injection of STZ; The other30rats received no treatment served as normal controls. Random blood glucose measured after96hours from rat tail veins, After96hours random blood glucose>16.67mmol/L identified as a successful diabetes model. All rats were fed normally, after6weeks,9weeks and12weeks, randomly selected10rats and placed in metabolic cages, collected and weighed24h urine. After the measurement of body weight、blood sugar, the rats in each group were underwent urodynamic measurement, measurement indicators include the bladder threshold capacity、residual urine、bladder voiding pressure and compliance. After the cystometry, cut the bladder at the posterior urethral, the specimens were divided into four parts. Part of the sample were prepared for HE staining and masson trichrome special staining, observe the bladder mucosa and detrusor of collagen、elastin changes under light microscope; part of the specimens were prepared for electron microscopy to observe ultrastructure changes of the detrusor; The level of NGF protein expression in bladder tissue NGF mRNA product content was measured by western blot and RT-PCR technique after6weeks、9weeks and12weeks.Results:The diabetic rats model was successful, the diabetic rats began to drink more, eat more, and show polyuria, weight loss and emaciation. At each check point, diabetic rats significantly weight less than the normal group, urine output was significantly increased.(1) urodynamic results:After6、9、12weeks, urodynamic examination found that in diabetic rats the maximum bladder capacity (threshold volume) increased significantly than the normal group and gradually increase with the extension of the diabetic course; the diabetic maximum bladder pressure at all check points was significantly lower than the normal group and decreased with the diabetic course; bladder compliance of the diabetic rats at all check points increased than the normal group; bladder wet weight and residual urine volume at each check point increased significantly compared with the normal group and showed an increasing trend with the diabetic course.(2) The light microscope performance of the diabetic bladder:a lot of eosinophilic cells infiltrated in the submucosa, lamina propria congestion and edema. The detrusor muscle cell hypertrophy, smooth muscle layer is2-3times as thick as the normal group, the muscle bundle show a diverse、 disorganized and loose morphology, muscle bundle fracture also can be observed (3) electron microscopy performance in diabetic bladder:mitochondria in smooth muscle cells showed swelling to different extent, reduced matrix density of mitochondrial cristae and shorter sparse or even disappeared. Some mitochondria presented matrix cavitation. The lesion aggravated with the diabetic course.(4) Western-blot analysis and RT-PCR results were found that, in bladder tissue,NGF protein and NGF mRNA product content decreased significantly and gradually decreased with the extension of the course.Conclusion:The early diabetic rats can present deceased bladder contractility and detrusor morphological changes, showing early diabetic detrusor damage. NGF in the bladder tissue of diabetic rats showed a gradual downward trend with the extension of diabetic course, a clear correlation between the NGF and development of diabetic bladder cystopathy can be founded.