Study On The Safety Of Balloon Compression In Rectum Tube Of Rats

Objective:Our objective was to compare the effect of different compression time of balloon tamponade in the rectal cavity of rats,and to provide experimental data and clinical guidance for the safe use of balloon compression in treatment of rectal bleeding.Methods:The rats were randomly divided into the control group?n=6?and experimental groups?n=36?.According to the compression time,the experimental groups were divided into group A?4-hour?,group B?2-hour?and group C?1/2-hour?with 12 rats in each group.Six rats in each group were killed immediately after compression,namely group A1,B1 and C1.The other 6 rats in each group were fed for 15 days before killed,namely group A2,B2 and C2.The balloon device was made by nasal catheter and latex finger cover.Syringe,sphygmomanometer and the balloon device were connected with the three connections of the T-branch tube respectively.In order to avoid secondary compression and ensure each rat of experimental group was compressed only once,6 SD rats?labeled as?1?-?6?,neither included in the control group nor experimental groups?were selected for Doppler ultrasound assisted pressure measurement to determine the P value and were no longer involved in the balloon compression experiment.Color Doppler ultrasound was used to detect rectal blood flow.The frequency of ultrasonic probe was adjusted to 15.0MHz and the image was CDFI mode.The ultrasonic probe was placed around the anus of rats with coronal plane.After abdominal anesthesia with 2%sodium pentobarbital?40mg/kg?,the balloon device with liquid paraffin was gently inserted from the anus into the rectum of rats with the depth of 2 cm,and the rectum ultrasonic blood flow images in resting state were measured.Gas was injected into the balloon through a syringe,which made the balloon inflate and press the rectal mucosa.When the image showed that the blood flow signal in the rectal cavity was just blocked,the minimum pressure value of blocking blood flow of rats labeled as?1?-?6?was taken.The mean value was set at P=130mmHg,which was taken as the uniform pressure value in subsequent balloon compression experiment.According to different compression time of 4hours,2 hours and 1/2 hour,the researchers used the balloon device to compress the rectal wall under same pressure?P=130mmHg?.After compression,the levels of blood routine test and coagulation function test in blood of rats were measured,including WBC,NEU,RBC,HGB,HCT,PLT,PCT,PT,APTT,TT,Fib,PT-INR.The levels of TNF-?,IL-1?and 5-HT in the rectal tissue were measured with ELISA using commercially available kits.After compression,the rectal tissue which was 2 cm above anus was removed.The changes of rectum mucous were evaluated by rectal mucous damage score,gross observation and HE staining.The remaining 6 rats in each group continued to be raised normally after compression,and the blood and rectal tissue were collected and tested after 15 days.The vital signs of the rats in the experimental group were observed during the compression.The general condition and anal appearance of the rats were observed after the compression.If the rats died,the cause of death was recorded and analyzed.Results:1.Blood routine test and coagulation function test:each group was compared in pairs,there was no significant difference and no statistical significance in the related indicators.2.IL-1?,TNF-?:Compared with the control group,TNF-?and IL-1?levels in rectal tissue significantly increased in group A1,B1,A2?P<0.05?but no significant difference was found in group C1,B2,C2.Compared with group A1,TNF-?and IL-1?levels in rectal tissue significantly decreased in group C1,A2?P<0.05?but no significant difference was found in group B1.Compared with group B1,TNF-?and IL-1?levels in rectal tissue significantly decreased in group C1,B2?P<0.05?.Compared with group C1,there was no significant difference in group C2.3.5-HT:Compared with the control group,5-HT levels in rectal tissue significantly increased in group A1,B1?P<0.05?but no significant difference was found in group C1,A2,B2,C2.Compared with group A1,5-HT levels in rectal tissue significantly decreased in group C1,A2?P<0.05?but no significant difference was found in group B1.Compared with group B1,5-HT levels in rectal tissue significantly decreased in group C1,B2?P<0.05?.Compared with group C1,there was no significant difference in group C2.4.Rectal mucous damage score:Compared with the control group,rectal mucous damage score significantly increased in group A1,B1,C1?P<0.05?but no significant difference was found in group A2,B2,C2.Compared with group A1,rectal mucous damage score significantly decreased in group C1,A2?P<0.05?but no significant difference was found in group B1.Compared with group B1,rectal mucous damage score significantly decreased in group C1,B2?P<0.05?.Compared with group C1,rectal mucous damage score significantly decreased in group C2?P<0.05?.5.Macroscopic observation:Compared with the control group,macroscopic changes including diffuse hyperemia,erosions and ulcers were observed in group A1 and B1.Smooth rectal mucosa with a little hyperemia was observed in group C1 and A2.Smooth rectal mucosa without hyperemia,edema and ulcer was observed in group B2 and C2.6.HE staining:Compared with the control group,the epithelium was uncontinuous and the rectal mucosal glands were disarranged in group A1 and B1.Other prominent changes in the two groups included varying degrees of congestion in mucosa,edema in the submucosa and infiltration of inflammatory cells.In group C1 and A2,the epithelium was continuous and complete,and the glands were orderly arranged.There was no obvious edema or hemorrhage in the submucosa.In group B2 and C2,the epithelium was continuous and the structure was clear.The mucosa layer and submucosa were complete without obvious edema,hemorrhage and inflammatory cell infiltration.7.Behavioral presentation and anal function:the rats of the experimental group had vital signs,and there was no abnormal death during compression.When the balloon was removed,the anal canal diameter increased,and 1 case of anal bleeding occurred in group A1.1 case died in group A2 on the second day after compression.The other rats in this group were in poor mental state with reduced activity,food and water,severe perianal pollution from 1^st day to 7^thh day after compression.From 8^th to 15^th,the mental activity,eating,drinking and perianal pollution gradually improved except that serious anal malformation occurred in one case.Behavioral presentation and anal function of the rats in group B2 were not good from 1^st day to 7^thh day,but gradually returned to normal from 8^th day to 15^th day.Behavioral presentation and anal function of rats in group C2 were normal.Conclusion:1.When the pressure was not more than 130mmHg and the time was less than 4 hours,the compression method had no significant effect on Blood routine test and coagulation function test of rats.2.When the pressure time was more than 2 hours,TNF-??IL-1?in the rectal tissues would increase and cause intestinal mucosal injury,leading to inflammatory response.3.When the time was more than 2 hours,changes in visceral sensation mediated by 5-ht would occurred.If the time was not more than 4 hours,the changes would return to normal.4.The longer the time,the higher degree rectal mucosa of injury and the more obviously the morphological changes.If the time was not more than 4 hours,the injury would basically heal itself.5.Excessive time could lead to changes of behavioral presentation and anal function.When the pressure reached 130mmHg and the time reached 4 hours,it causes rectal rupture,perianal pollution and even irreversible anal malformation.To ensure the safety of patients,it is necessary to be careful of the prolonged use of the balloon device,otherwise it will cause side effects.