Experimental Neurogenic Bladder in Rats and Effect of Robaveron, a Biological Prepared from Swine Prostate, on It

Abstract

An experimental neurogenic bladder was induced in rats by an intraspinal injection of 10% phenol-glycerin solution. The functional and biochemical changes in the bladder were studied in vivo and ex vivo, and the effect of Robaveron, a biological prepared from swine prostate, on these changes were examined. The forced voiding pressure in the control rats which had been caused by the neurogenic bladder was reduced to 1/4-1/5 that of the intact animals. Robaveron recovered a decrease in the pressure, and the effect of 150-250 mg/kg, p.o., corresponded nearly to that of 40 mg/kg. i.m. In the ex vivo study with the strips of isolated neurogenic bladder muscle, the time required to cause 50% of the maximum contraction by transmural electric stimulation prolonged to about four times that of the intact one. Such a prolongation was recovered by Robaveron in a dose-dependent fashion, and the effect of Robaveron given p.o. corresponded to about 1/6 that of the drug given i.m. No change in Ca2+-influx, was found, although Ca2+-efflux was inhibited in the strip of neurogenic bladder muscle. Such an inhibition was significantly relieved in that of animals treated with Robaveron. In the neurogenic bladder rat, the ratio of bladder weight to body weight increased, and the activities of total ChE and AChE in the bladder muscle decreased, on which Robaveron did not show any influence. Phasic and tonic contractions in the strips of intact rat bladder and guinea pig ileum were inhibited by La3+, particularly phasic response in both the strips. Robaveron recovered the inhibition in a dose-dependent fashion. The present study suggests that the urinary dysfunction in neurogenic bladder may be caused not only by nervous disorders but also by changes in the bladder muscle itself. Robaveron was found to be effective for most of such changes. These findings may support the clinical efficacy of Robaveron for improving the attenuated bladder function.