Effect of increased intra-abdominal pressure on urinary system development in fetal rabbits

Aim: To investigate the effect of increased intra-abdominal pressure (IAP) on the fetal urinary system. Materials and methods: Pregnant rabbits (15-day gestation) were used. Control (n = 5) and experimental (EG, n = 4) groups underwent intraperitoneal catheter placement. The IAP was increased by intraperitoneal air insufflations during the third trimester in the EG. At term, organ weight and organ weight/body weight (BW) ratios were noted, histological examination of the urinary system organs was performed, and the apoptotic indexes were calculated. Results: BW and total renal weight were significantly increased in the EG (38.65 +/- 8.34 g vs 49.36 +/- 8.81 g, p = 0.008; and 0.406 +/- 0.132 g vs 0.531 +/- 0.129 g, p = 0.02). Total renal weight/BW ratio did not differ between groups (0.0103 +/- 0.001 vs 0.0107 +/- 0.001; p = 0.33). Bladder weight and bladder weight/BW ratio was also significantly increased in the EG (0.067 +/- 0.014 g vs 0.114 +/- 0.026 g, p = 0.00; and 0.00175 +/- 0.00026 vs 0.00229 +/- 0.00036, p = 0.001). Immature glomeruli and collecting tubules, and a thin and underdeveloped muscular layer in the ureter and bladder were encountered in the EG, and the apoptotic cell index was significantly increased (p < 0.05). Conclusion: Increased IAP has an adverse effect on fetal urinary system development, and may play a role in the pathogenesis of various congenital abnormalities of the urinary system. (C) 2011 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.