title: [Effects of diabetic hyperlipidemia on bladder function and its possible mechanisms in a male rabbit model].
abstract: OBJECTIVE
  To evaluate the effects of chronic hyperlipidemia on bladder function and its possible mechanisms and examine the functional and histological changes of bladder in a diabetic hyperlipidemic model.
  
  
  METHODS
  A total of 30 male New Zealand white rabbits (2.5 to 3.0 kg) were numbered sequentially and randomly divided into 2 groups (hyperlipidemic group and control group). Then urodynamic test and detrusor strip contraction study were performed to assess bladder function.Histological studies of bladder and internal iliac arteries were performed with hematoxylin and eosin staining. The ultrastructure of bladder detrusor tissue was examined by transmission electron microscopy. Also the bladder tissue M2, 3-muscarinic receptor protein levels were examined by immunohistochemistry.
  
  
  RESULTS
  After 12 weeks, the urodynamic test of the test group showed significantly increased non-voiding contractions (10/14 vs 1/13, P < 0.05) and decreased compliance ((2.16 ± 0.17) vs (4.18 ± 0.21) ml/cm H2O, P < 0.01) versus the control group. The functional experiments showed that carbachol-induced contractions significantly decreased in hyperlipidemic rabbits than those in controls. As to the relaxant actions of selective muscarinic receptor M3 antagonist solifenacin, the bladder strips of hyperlipidemic rabbits were significantly more sensitive than those of the controls.Histological examination showed thickened intima of internal iliac arteries, urothelial disruption and mild fibrosis in the hyperlipidemic rabbits. Transmission electron microscopy of hyperlipidemic bladder muscle tissues showed swollen mitochondrial damage. As to the immunohistochemical results, compared with the control group, the hyperlipidemic group showed significantly increased M3 receptor expression both in bladder urothelium (146 ± 14 vs 108 ± 9, P < 0.01) and smooth muscle layer (131 ± 17 vs 116 ± 15, P < 0.05) . And the expression was more obvious in urothelium layer.
  
  
  CONCLUSIONS
  Involuntary detrusor overactivity with decreased bladder compliance and decreased contractions of detrusor are present in hyperlipidemic rabbits. And chronic bladder ischemia and increased M3 receptor expression may contribute to bladder dysfunction.
authors.affiliation: Department of Urology,Qilu Hospital of Shandong University,Jinan 250012, China.
authors.forename: Xi-gao
authors.initials: XG
authors.lastname: Liu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Tang
authors.forename: Wei
authors.initials: W
authors.lastname: Yu
authors.affiliation: Department of Urology, Peking University First Hospital, Institute of Urology, Peking University, Beijing 100034, China. Email: wushiliangjsh@263.net.
authors.forename: Shi-liang
authors.initials: SL
authors.lastname: Wu
authors.affiliation: Department of Urology,Qilu Hospital of Shandong University,Jinan 250012, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Jin
mesh_terms: D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology; D006949:Hyperlipidemias / Q000378:metabolism* / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction; D011817:Rabbits; D043587:Receptor, Muscarinic M3 / Q000378:metabolism; D001743:Urinary Bladder / Q000503:physiopathology* / Q000648:ultrastructure; D053201:Urinary Bladder, Overactive / Q000503:physiopathology
chemical_list: D043587:Receptor, Muscarinic M3