联用肠道旋毛虫感染和急性应激构建肠易激综合征大鼠模型

Establishment of irritable bowel syndrome rat model by combination of intestinal infection with Trichinella Spiralis and acute stress

目的联合一过性肠道旋毛虫感染和急性应激刺激构建肠易激综合征（IBS）大鼠模型。方法旋毛虫灌胃法感染成年雄性BrownNorway（BN）大鼠，并于100d后给予2h急性寒冷束缚应激，构建感染后应激大鼠模型。同时设立一过性感染大鼠和正常大鼠作为对照，每组6只。100d时四通道胃肠功能测压仪在体检测各组大鼠结肠运动功能，包括在静息、球囊扩张时的结肠最大收缩波幅、总收缩面积、收缩次数以及总收缩时间。同时测定内脏疼痛阚值，即结直肠球囊扩张法测定大鼠在腹壁回撤反射（AWR）评分为3分时的球囊扩张容积。结果旋毛虫感染10d时，肠黏膜充血、水肿，上皮结构受损；100d后，一过性感染组及感染后应激组引起的大鼠肠道急性期组织学变化均恢复正常。但一过性感染及感染后应激刺激仍可致大鼠结肠运动及内脏感觉功能异常，且感染后应激刺激可使上述异常加重。感染后应激组的最大收缩波幅、总收缩面积、收缩次数均显著高于一过性感染组[（41±17）mmHg、（7693±2822）mmHg·s、（9．5±2．6）次比（22±6）mmHg、（5092±1687）mmHg·s、（6．6±3．1）次，均P=0．000，1mmgHg=0．133kPa]，且AWR3分扩张容积进一步下降[（2．25±0．29）mlvs（2．52±0．32）ml，P=0．004]。依据正常对照大鼠各指标的测定值估算90％正常值范围发现：感染后应激组大鼠结肠运动各参数及内脏痛觉的异常率也较一过性感染组更高（50．0％～87．5％和100％比25．0％～37．5％和90．0％）。结论一过性肠道旋毛虫感染后急性应激所致的大鼠肠功能紊乱模型符合IBS的主要生物学特征，并能再现应激因素加重大鼠感染后的肠道运动功能紊乱和内脏高敏感，是用于IBS发病机制研究的理想模型。

Objective To establish the irritable bowel syndrome （IBS） rat model by the combination of acute stress and transient intestinal infection with Trichinella Spiralis （T. S. ）. Methods The rat modal of acute cold restraint stress post-infection （ PI ± ACRS） was established as following ： the intestinal infection with 1500 T. S. in 1 ml saline to adult male BN rats was performed at Day 0 by gastric lavage. Then a 2-hour stimulus of ACRS was administered at Day 100. Age matched transiently infected without stress rats （PI） and normal rats served as controls （CON） （n =6, for each）. After anesthesia, all the rats underwent colonic manometry in vivo at Day 100. The colonic pressures at 3 different states （ baseline for 20 min ; 1ml balloon distension stimulation for 5 min and 2 ml balloon distension stimulation for 20 rain） were traced with a 5-minute interval between each two. The following parameters were recorded： （ 1 ） Duration （ Dur. ） ： total time of contractions during each state. （ 2 ） Maximum （ Max. ） ： highest amplitude of contractional waves （ mm Hg ） . （ 3 ） Area ： area under contraction waves. （ 4 ） Number （Num.）： frequencies of contraction wave during each state. The visceromoter response to colorectal distension （CRD） was analyzed at Day 100 post-infection. And the distension volume of AWR 3 was detected for 5 times with a 20-min interval in each rat. Results The histological damage of intestine induced by T. S. infection is transient. Although such acute infectious features as epithelial edema, hyperemia and marked eosinophil infiltration appeared at Day 10 PI, the histological changes almost recovered at Day 100 PI in both the PI group and the PI ± ACRS group. Both the stimuli of transient infection and the ACRS postinfection induced intestinal dysmotility and visceral hypersensitivity. The ACRS post infection further worsened the transiently induced infection. The parameters of Num, Max and Area in the PI ± ACRS group were all significantly higher than those of the PI group [ Max： （41 ± 17） mm Hg vs （22 ±6） mm Hg, P = 0. 000; Area： （7693 ±2822） nun Hg · s vs （5092 ±1687） mm Hg·s, P =0.000; Num： 9.5 ±2.6 vs 6. 6 ± 3.1, P = 0. 000 ] ; so was the distension volume of AWR3 [ （2. 25 ± 0.29） ml vs （2.52 ± 0. 32） ml, P = 0. 004 ]. As compared with the range of normal values from controls, the abnormality rates of motility parameters and visceral threshold in PI ± ACRS group also had an larger increment than those of the PI group （PI＋ACRS： 50. 0% - 87.5% and 100% respectively, PI： 25. 0% - 37.5% and 90. 0% respectively）. Conclusion The pathophysiological changes in the PI＋ACRS rats are consistent with those of IBS. Aggravated by psychological factors, these rats reproduce the symptoms of intestinal dysmotility and visceral hypersensitivity. A proper animal model has been established for the investigation of IBS.