Effects of partial bladder outlet obstruction on detrusor biomechanical properties / 中华泌尿外科杂志

ABSTRACT

Objective To establish a stable and repeatable experimental partial bladder outlet obstruction(p-BOO)rat model and to figure out the impaction of p-BOO on detrusor biomechanical properties.Methods P-BOO animal model was established by partialligation of the bladder neck of male Wistar rats,a urethra stricture by laying a trochar outside of bladder neck.The rats were divided into sham-operation group,P-BOO 6 weeks group(P-B006W)and P～BOO 12 weeks group(PBOO12W)by time.Cystomety was performed in P-BOO6W and the rats were divided into detrusor instability group(DI)and destrusor stability group(DS)on the basis of destrusor stability.The active contraction of detrusor muscle stripes to Carbachol was recorded with tensile foree transducer.The compliance and maximum volume of bladder,bladder leak point pressure were examined by filling cystometry.Results The bladders of P-BOO animal model demonstrated typical post obstruction alterations after P-BOO.The maximum volume increased significantly in DI group(10.8±3.0)ml,DS group(10.3±1.9)ml and P-B0012W group(9.5±2.3)ml as compared with that in sham-operation group(2.1±0.3)ml(P＜0.05).The bladder leak point pressures were significantly higher in DI group(39.4±7.1)cm H2O,DS group(35.9±6.2)cmH2O and P-B0012W group(48.6±9.5)cm H2O as compared with that in sham-operation group(16.2±2.1)cm H2O(P＜0.05).The bladder compliances were significantly higher in 13I group(0.27±0.08)ml/cm H2O,DS group(0.29±0.05)ml/cm H2O and P-BOO12W group(0.21±0.05)ml/cm H2O as compared with that in sham-operationgroup(0.13±0.03)ml/cm H20(P＜0.05).The detrusor contractile force of DI group was significantly lower than that in the sham-operation group and DS group(P＜0.05).No definite contraction wave was detected in the detrusor muscle of P-BOO12W group(amplitude＜0.05g).Conclusions There are 2 different types of the detrusor contraction after P-BOODI group with impaired contraction and conversely DS group with compensatory contraction.The contractility of detrusor muscle will be damaged and even irreversible contractile function incapacitation will occur if the obstruction is not removed.The effect of bladder stability tO bladder compliance is inconspicuous and there is close correlation between bladder compliance and bladder capacity.