| Objective:The aim of this study is to build the rat animal model of neurogenic bladder by the way of transecting suprasacral spinal cord and observe the change of bladder weight, detrusor leak point pressure, compliance,bladder wall organizational structure and the number of ICC cells after transaction. We intend to study the pathophysiological mechanisms of development. And to explore the effect and the mechanism of ICC cells on bladder compliance in neurogenic bladder obstruction rats.We look forward to finding appropriate intervention point to relief the change of bladder wall fibrosis, protecting the bladder compliance. In order to improve the treatment of the neurogenic bladder and provid theory basis for further experiments.Methods:A total of40Wistar white female rats, the weight between210g and220g, which were randomly divided into2groups. Group A is normal group, which has8rats. Group B is suprasacral spinal cord transaction group,which has32rats. The main steps:Female rats were weighted^anesthetized and fixed on the operation table with supine position. Bladders from adult female Wistar rats post suprasacral spinal cord transection (T8laminectomy) or sham-operated controls (shams) were obtained Animals were assisted with bladder voiding for2weeks by abdominal compression5times each day until micturition reflexes emerged and were injected daily, for the first week with gentamicin (0.5mg/kg). After6weeks, urodynamic examinations were carried out in all groups. rats were weighed, killed by cervical dislocation; the bladders were removed, weighed. HE staining, VG staining, and Vaehoeff staining, light microscope observing structure of smooth muscle and fibrous connective tissue change. Immunofluorescence, observing the number of ICC cells on the bladder walls. Selecting five fields in each photograph under×400high power fields, measuring the number of the ICC cells by Image-Pro Plus6.0software.Results 1. We succeeded in building the rat animal model of neurogenic bladder by the way of transecting suprasacral spinal cord and carrying urodynamic examinations to the rats’bladder2. Bladder Compliance:the results of the urodynamic examinations showed that12rats are high compliance bladder,6rats are low compliance bladder, and4rats are normal compliance bladder. The bladder compliance was significant decreased in group of low compliance bladder than group of high compliance bladder and group of shams(P<0.01). Detrusor leak-point pressure:group of high compliance bladder show significantly lower than shams (P<0.01), there were no obvious difference between group of low compliance bladder and shams (P>0.05)3. Morphological study of the bladder wall showed that bladder structure and function altered significantly, bladder weight increased significantly(P<0.01), bladder wall obvious accumulation, bladder capacity significantly increased in group of high compliance bladder. Significant differences were not found in animal mass pre-surgery(P>0.05); however, post-surgery SCI animals were significantly lighter than shams(P<0.01), moreover the bladder-to-body mass ratio was significantly larger in SCIs(P<0.01). We observed the detrusor appeared different degree of muscle atrophy after6weeks of suprasacral spinal cord transaction by light microscope. After suprasacral spinal cord transaction, the percentage of fibrous connective tissue was increased in group of high and low compliance bladder, bladder wall remolding causing the bladder fibrosis, bladder weight increased significantly. The number of ICC cells increased significantly in group of low compliance bladder (P<0.01), and decreased significantly in high compliance bladder group(P<0.01).Conclusions1. The effect to bladder compliance of the suprasacral spinal cord transaction can be characterized by two types of high resilience and low compliance according to urodynamic examinations.2. Urodynamic examinations of neurogenic bladder showed:the bladder capacity reduced, detrusor pressure increased in group of low compliance bladder; the bladder capacity increased, detrusor pressure reduced in group of high compliance bladder. 3. The detrusor appeared different degree of muscle atrophy after suprasacral spinal cord transaction by light microscope. The percentage of fibrous connective tissue was increased in group of high and low compliance bladder, bladder wall remolding, causing the bladder fibrosis, so that influent bladder compliance.4. After the suprasacral spinal cord transaction, the number of ICC cells changed among groups, it may be associated with change of bladder compliance. |
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