Abstract
Bladder dysfunction is known to be a frequent manifestation of autonomic neuropathy in diabetic patients. In this study we developed a new system of cystometric analysis to evaluate bladder function in diabetic rats, which could be used for animal experiment on diabetic cystopathy.
Diabetic rats were produced by intravenous injection of streptozotocin 60mg per kg body weight. Some of the diabetic rats were treated with subcutaneous insulin injection between 8th and 12th week after the induction of diabetes. The system of cystometric analysis was composed of a 26 G needle connected with plastic tubes, injector, transducer, polygraph and recorder. On the 4th and 12th week after the induction of diabetes, midline laparotomy was performed and the bladder was exposed under anesthesia with intraperitoneal pentobarbital injection. After the 26 G needle connected with the injector containing saline was inserted into the bladder, saline was infused stepwesly through one plastic tube, and the intravesical pressure was measured through another plastic tube connected to a transducer. This procedure was repeated until the beginning of urine voiding from the urethra.
The volume at voiding was 0.7ml±0, 4ml in normal rats and 4.5ml±1.7ml in diabetic rats in the 4th week (Normal vs DM, p<0.05), while the pressure at voiding was not significantly different between the two groups. Similar results were obtained on 12 th-week experimental rats. Insulin treatment improved the cystometric abnormality. However, there was a remarkable increment of urine volume in diabetic rats, which might physically modify the results. Therefore we produced nondiabetic polyuric rats by giving 5% glucose solution freely and performed the same examination in order to evaluate the effect of polyuria on the cystometric results. No cystometric abnormality was detected in non-diabetic polyuric rats by our system.
These results suggest that this system for cystometric analysis may be a useful means of investigating bladder dysfunction in diabetic rats.
