Inosine protects bladder structure and function in rats with diabetic cystopathy / 医学研究生学报

ABSTRACT

Objective At present,there is still a lack of effective means for the treatment of diabetic cystopathy,and to find natural antioxidants for this purpose has become a hot spot in research. This study is to investigate the protective effect of inosine on the bladder of diabetic rats and its antioxidative stress mechanisms. Methods A total of 60 adult male Sprague-Dawley rats were ran-domly divided into three groups of equal numbernormal control,diabetes mellitus(DM) model control,and inosine intervention. The DM model was made by intraperitoneal injection of streptozotocin at 60 mg/kg. The DM model controls were injected with saline while the model rats in the intervention group with inosine, all at 75 mg/kg, ip,bid. After 4 and 8 weeks of treatment, the bladder tissues were collected from the rats for examination of the structural changes by HE staining,determination of the expressions of c-kit and nerve growth factor (NGF) by immunofluorescence assay, and observation of the ultrastructure of the bladder tissue under the electron microscope,de-tection of the cell apoptosis by TUNEL,and measurement of the con-tents of malondialdehyde (MDA),superoxide dismutase (SOD),and glutathione (GSH). Results HE staining indicated signifi-cant mucosal hyperplasia, disordered arrangement, loose structure, fracture, expanded intervals and collagen fiber filling of muscle bundles,muscular atrophy,lymphocytes infiltration,vascular hyperplasia and congestion,and few muscle bundles,while electron mi-croscopy manifested disordered arrangement, interrupted connection, mitochondrial vacuolation in muscular and interstitial cells, shrinkage of nuclear membrane,disappearance of nucleoli,and irregular chromatin margination and condensation in the bladder tissues of the DM rat models. Immunofluorescence assay showed that the signals of c-kit and NGF were reduced in the DM models as compared with those in the normal controls. After 4 and 8 weeks of intervention,the cell apoptosis rate was significantly higher in the DM model control ([1.68±3.04]% and [10.51±0.90]%) and inosine-treated rats ([7.00±1.72]% and [7.24±1.66]%) than in the normal controls ([4.65±3.04]% and[5.48±2.00]%),but remarkably lower in the inosine-treated than in the DM model controls(P<0.01). The contents of SOD and GSH were increased(P<0.05) while that of MDA decreased markedly in the DM models(P<0.05),but the former decreased (P<0.05) while the latter increased significantly in the inosine intervention group as compared with the DM model control group (P<0.05). At 8 weeks,the contents of SOD and GSH were remarkably lower in the DM model than in the normal con-trols (P<0.01),while that of MDA markedly higher than in both the normal control and inosine intervention groups (P<0.01). The wet weight of the bladder was significantly increased in the DM model and inosine intervention groups in comparison with that of the nor-mal controls(P<0.01). Conclusion Oxidative stress plays an important role in the development and progression of diabetic cystopa-thy. Inosine can protect the bladder structure and function of the DM rat by reducing oxidative stress and injury to the bladder tissue.