Establishment Of Animal Model Of Low-compliance Bladder In Male Rabbit

Objective:The experiment is intended to build the rabbit animal model of low compliance bladder by the way of obstructing bladder outlet and observe the changing of bladder weight, volume, detrusor leak point pressure and compliance after obstruction. We intend to study the possible mechanism and the key point of its pathophysiology. We look forward to finding appropriate intervention point to slow down or relief the change of storage function after BOO. Methods:28 male New Zealand White rabbits were divided randomly into 3 groups. Among of them,8 rabbits were contrast group A; 10 rabbits were operated for BOO for 5 weeks as group B; 10 rabbits were operated for BOO for 14 weeks as group C. Group B and C underwent partial outlet obstruction creation by standard methods. A suprapubic midline incision was made to expose the bladder and urethra. In the obstruction,1-0 silk suture was loosely tied around the catheterized urethra. The catheter was then removed and the incision closed.The contrast group were done only dissection without ligation. Group B was given urinary dynamics tests 5 weeks after operation. Group C was tested respectively at the end of 8,12,14 weeks. After test, we obtained the bladder specimen, HE staining, light microscope observing structure of smooth muscle and fibrous connective tissue change. ResultsThe weight increased significantly in obstruction group B (16.9±4.4) g and C (14.1±2.3) g as compared with that in control group (2.7±0.5) g, P<0.01.The bladder volume increased significantly in obstruction 5 weeks (67.0+ 17.3) ml and 8 weeks (57.8±16.9) ml as compared with that in control group (36.3±14.7)ml, P<0.01. The volume of obstruction 14 weeks(20.9±6.2) was less than that of control group (P<0.05). And the bladder volume of obstruction 12 weeks and 14 weeks was less than that of obstruction 5 weeks and 8 weeks, P<0.01.The compliance firstly increased in obstruction 5 weeks (5.16±1.41) ml/cmH2O and 8 weeks (4.39±1.72) cm/H2O as compared with control group (2.91±0.71) ml/cmH20, P<0.01, P<0.05.The compliance in obstruction 12 weeks(1.53±0.49) ml/cmH20 was less that in control group,P< 0.05,and especially the compliance in obstruction 14 weeks group(1.21±0.44) ml/cmH20 was less than that in control group, P<0.01.Conclusions BOO animal model established by partial ligation of the bladder neck of adult male rabbits is simple, stable and suitable for studies of bladder outlet obstruction.The structure and function of the bladder was significantly changed 14 weeks after operation:the weight and maximum volume of bladder in obstructed group was significantly increased. The detrusor leak point pressure was increased. And the compliance firstly increased and in the end decreased and the wall of urinary bladder was got fibrosis.