title: Diabetes-induced alternations in biomechanical properties of urinary bladder wall in rats.
abstract: OBJECTIVE
  To determine whether diabetes mellitus and the associated changes in bladder function will trigger bladder wall tissue remodeling and concomitant alterations in the mechanical properties. We investigated the time course of changes in function and mechanical properties of diabetic and diuretic rat bladders using both in vivo and in vitro techniques
  
  
  METHODS
  Cystometry was performed at 2, 4, and 8 weeks on female Sprague-Dawley rats that had received either a single injection of streptozotocin (65 mg/kg intraperitoneally) or 5% sucrose in drinking water for the duration of the experiments. At each point, the biaxial mechanical properties of 10 x 10-mm tissue specimens obtained from the posterior part of bladder wall were quantified. The changes in overall tissue compliance and mechanical anisotropy as a function of time were examined
  
  
  RESULTS
  Both diabetic and diuretic conditions led to increases in bladder weight, bladder capacity, and in vivo compliance compared with the controls at all points tested. Under biaxial loading, all bladder wall tissues exhibited a nonlinear stress-strain relationship and mechanical anisotropy, with greater tissue compliance in the circumferential direction than in the longitudinal direction. Although the compliance of the bladder wall increased progressively and synchronously in both diabetic and diuretic bladders for < or = 4 weeks, only the diabetic bladders continued to increase the compliance for < or = 8 weeks (diabetic 0.64 +/- 0.04 vs diuretic 0.48 +/- 0.05, P = .03)
  
  
  CONCLUSIONS
  The results of our study have shown that diuresis mainly contributes to the "early" changes of mechanical properties of the bladder, with diabetes inducing additional "late" changes of mechanical properties of the rat bladders after 4 weeks.
authors.affiliation: Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Chung Cheng
authors.initials: CC
authors.lastname: Wang
authors.forename: Jiro
authors.initials: J
authors.lastname: Nagatomi
authors.forename: K Khashayar
authors.initials: KK
authors.lastname: Toosi
authors.forename: Naoki
authors.initials: N
authors.lastname: Yoshimura
authors.forename: Jui Hsiang
authors.initials: JH
authors.lastname: Hsieh
authors.forename: Michael B
authors.initials: MB
authors.lastname: Chancellor
authors.forename: Michael S
authors.initials: MS
authors.lastname: Sacks
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D005260:Female; D051381:Rats; D017207:Rats, Sprague-Dawley; D001743:Urinary Bladder / Q000503:physiopathology*