Captopril reduces deposition of collagen in lamina propria and muscular layers of the bladder and ureter in neonatal dogs with partial urethral obstruction

Abstract

It has been recognized that most boys with posterior urethral valve ablation have varying degrees of ureteral dilation and abnormal bladder function. It has been shown that deposition of collagen in the bladder layers increases the intravesical pressure that is transmitted to the pelvicalyceal system. The purpose of this study was to evaluate, using stereological methods, the effect of captopril on prevention of collagen formation in different layers of the ureter and bladder under conditions of partial urethral obstruction (PUO). PUO was induced in 10 neonatal dogs. These animals were then divided into two equal groups: the experimental group received captopril (35 mg/kg/day) and the positive control group received no treatment. After 6 weeks, the neonatal dogs underwent left nephroureterectomy and cystectomy. The ureter and bladder volumes, the volume fraction and absolute volume of the histological parameters of the ureter and bladder, the collagen content of the lamina propria, muscular and adventitial layers, and the muscle content of the muscular layer were estimated using stereological methods. The ureter and bladder volumes, the volumes of the layers including mucosa, lamina propria and muscular layer adventitia, the muscle content of the muscular layer and the collagen content of the adventitial layer did not show any significant differences between the groups. The collagen content (absolute volume) of lamina propria and muscular layer in the experimental group was lower than that in the positive control group for both the ureter and bladder. Administration of captopril decreases the collagen content of the lamina propria and muscular layer in the ureter and bladder of neonatal dogs with PUO.