The Changes Of Urodynamics And Endothelin-1 In Neurogenic Bladder Caused By Spinal Cord Injury At The Early Time

ObjectiveTo explore the contents of endothelin-1(ET-1) in the blood and urine and the changes of urodynamics in spinal cord injury(SCI) at the early time(1～6week) by establishing an animal model of neurogenic bladder(NB),which can provide the evidence for diagnosis and treatment of the clinical patients with NB.MethodsFirstly,an animal model was established.20 female Wistar rats,4～5 months old with the average weight of 330～350g,were given suprapubic cystostomy separately.After the surgery,intraperitoneal injection of gentamicin with the dosis of 5000U/kg and the frequence of 1 times per day was given in the next 3 days.One week later,12 rats which were divided into experimental group had an operation of spinal cord(L_1～2) transection to set up an animal model of neurogenic bladder.The remaining eight rats which opened the dura mate of spinal cord only without injuring the spinal cord were as a control group.After the second surgery all rats were used to detect the ET-1 content in blood with ELISA method and carry out the urodynamic examination at the end of the second,forth and sixth week.The detection of ET-1 in urine was executed every week.After the surgery,intraperitoneal injection of gentamicin with the dosis of 5000U/kg and the frequence of 1 times per day were given in the next 7 days.Assist the rats of experimental group to urinate and defaecate by massaging their hypogastriums 3 times a day.All rats were given hindlimb functional assessment of behavior through Tarlov score standard.Compare the varieties of ET-1 contents in blood and urine and the changes in urodynamics before and after the operation between two groups.Results(1)General state of health(Tarlov score):Experimental group:all the rats gained 0 point in the next 3 weeks after operation,and some of them gained 1 point between third and forth week;all the rats scored 1 point after the forth week.Control group:all the rats scored 5 point.All the experimental rats appeared uroclepsia,urinary retention,fecal incontinence,hind limb edema,and so on.(2)urodynamic characteristics:â‘ At the second week:The bladder's capacity and compliance in experimental groups((7.81±0.77) ml and(0.364±0.043) ml/cmH₂O) were higher than the control group((2.89±0.15)ml and(0.093±0.014)ml/cmH₂O)(P＜0.05).At the sixth week:The bladder's capacity and compliance in experimental group((2.31±0.31)ml and(0.037±0.006)ml/cmH₂O) were significantly lower than the control group((2.86±0.13)ml and(0.092±0.011)ml/cmH₂O)(P＜0.05);â‘¡At the second week:The leak point pressure of detrusor in experimental group(63.750±7.213cmH₂O) was significantly higher than the control group(31.375±3.777)(P＜0.05).In the experimental group, detrusor hyperreflexia could be observed;â‘¢In the experimental group,detrusor hyperreflexia could not be observed at the second week and appeard at the forth(66.7%)and sixth week(91.7%).(3)The changes of the ET-1 in blood and urine:â‘ There was no significant difference in ET-1 content in blood at the second,forth and sixth week between two groups(P＞0.05).The urinary ET-1 content in experimental group was significantly lower than the control groups(P＜0.05);â‘¡In experimental group,the urinary ET-1 content at the second and forth week were lower than the content at the fifth and sixth week(P＜0.05).The urinary ET-1 content in experimental group has no significant difference between the fifth week and sixth week(P＞0.05);â‘¢The ET-1 content in blood and urine was no significant difference in the control group(P＞0.05).Conclusion(1)The period of spinal shock stage is 3 to 4 weeks after operation;(2)In experimental groups the bladder's capacity and compliance increase in spinal shock stage and decrease after spinal shock stage;(3)The leak point pressure of detrusor in experimental group increases and detrusor hyperreflexia could be observed after spinal shock stage;(4)ET-1 may play a role in the course of neurogenic bladder.ET-1 content in urine gradually reduces with the advancement of pathogenetic condition.At the early stage after spinal shock stage,ET-1 content in urine was in the stable state of low concentration.