脊損膀胱急性期における膀胱平滑筋の病態ならびに2,3薬剤の影響についての実験的研究

Abstract

The purpose of the present paper is to investigate the functional, histological and metabolic changes of cord bladder in the acute stadium of spinal injury. Spinal injury was produced on rabbits at the level of L5 by means of a new simple technique. Cystometrogram, histological findings of the bladder wall, histochemical activity of succinate dehydrogenase (SDH, modified method of Nachlas, Seligman et al.), that of phosphorylase (PhR, Takeuchi and Kuriaki's method) and chemical activity of phosphorylase (cPhR, medified method of Sutherland) in the bladder smooth muscle were observed both in normal and cord-injured rabbits, in the latter 5 days after the injury. Furthermore, the effects of atropine (0.15mg/kg), bethanechol (0.8mg/kg), and cocarboxylase (3mg/kg) on the above mentioned examinations were observed. The following results were obtained. 1) In normal rabbits, the maximum voiding capacity (MVC) was 62.7±9.4ml and the maximum voiding pressure 33.1±1.3mmHg. In the bladder wall of normal rabbits, smooth muscle had PAS positive substance, SDH was weakly positive, PhR was stronger in the muscle than in the mucosa and cPhR was 5.4±1.1. 2) The cystometorogram on the 5th day after injury showed hypotonic curves, increased MVC and decreased MVP, but did not show any autonomous waves. Histological examination revealed deformity, atrophy and ablation in the mucosa, edema, hemorrhage, proliferation of connective tissue and atrophy of the muscle layer. SDH and PhR were decreased and cPhR was 3.0±0.7. 3) After a single injection in normal rabbits, MVC was remarkably decreased by bethanechol and not changed by atropine, but the effect of cocarboxylase on MVC was indefinite, On the other hand, MVP was decreased by atropine, but effects of bethanechol and cocarboxylase were indefinite. The drugs had no effect on histological findings and enzyme activity in the normal bladder. After daily injection for 18 to 20 days, there was also no difference either in histological or histochemical findings by bethanechol and cocarboxylase, but by atropine, there was weak edema in the muscle layer, and SDH, PhR and cPhR were decreased. 4) Bethanechol in the daily doses of 0.8 mg/kg, which was not fatal to normal rabbits even after 20 days of daily injections, killed cord-injuried animals within 3 days after the beginning of daily injections. On the other hand, the half doses of bethanechol given to cordinjured animals showed a tendency to increase MVP and irregular waves in the cystometrogram. MVC remained unchanged. Histologically, there was no favorable influence of bethanechol; and moreover, it exhibited tendencies to decrease SDH, PhR and cPhR when compared with cord-injured animals which were given no drug. Cocarboxylase presented a tendency to repress the changes produced in the bladder by cord injury such as the increase in MVC, the decrease in SDH, PhR and cPhR or the appearance of muscle atrophy. The author concluded from the experiments described above that because the bladder smooth muscle has fallen into dysfunction and metabolic disturbances, the administration of cocarboxylase is useful for neurogenic bladder in the acute stadium, but bethanechol is not only insignificant but even harmful to function of the bladder in this stadium.