急性肠道旋毛虫感染后小鼠和大鼠内脏敏感性变化比较

目的通过观察旋毛虫肠道急性感染后不同时间点小鼠和大鼠内脏敏感性的变化,比较2者之间差异,探讨相似感染因素在不同种类动物之间可能通过不同途径导致内脏高敏感。方法旋毛虫幼虫包囊感染NIH小鼠(400条/只)和SD大鼠(8000条/只),分别于感染后2周、8周称体质量;通过腹壁回撤反应(abdominal with drawal reflex,AWR)评分评估感染前后不同时间点实验动物对结直肠扩张(colorectal distension,CRD)的内脏敏感性;处死实验动物,留取空肠、末端回肠、近端结肠、远端结肠进行HE染色观察肠道病理变化。结果 NIH小鼠及SD大鼠肠道感染后2周体质量增长率低于正常对照组(P值分别为0.021和0.092),感染后8周体质量增长与正常对照组差异无统计学意义(P值分别为0.596和0.827);2者感染后2周组肠道各部分炎性反应评分显著高于正常对照组,感染后8周组肠道各部分炎性反应评分与正常对照组差异无统计学意义。在扩张压力为40、60mmHg时,NIH小鼠感染后2周组及感染后8周组AWR评分显著高于正常对照组(CRD为40mmHg时,P值分别为0.000和0.010;CRD为60mmHg时,P值分别为0.000和0.014),以感染后2周组增高更为显著,差异有统计学意义;在扩张压力为40、60mmHg时,SD大鼠感染后2周组AWR评分显著低于正常对照组,差异有统计学意义(P值分别为0.046和0.035),而感染后8周组则显著高于正常对照组(P值分别为0.009和0.000)及感染后2周组,差异有统计学意义(P值分别为0.005和0.001)。结论 NIH小鼠和SD大鼠急性旋毛虫感染后8周炎性反应消退,内脏高敏感长期存在,但2者发展过程不同。本研究推测相似感染因素在不同动物之间可能通过不同途径影响内脏敏感性的变化。

Comparison of Changes in Visceral Sensitivity between Mice and Rats after Acute Intestinal Trichinella Infection

Objective Many studies show that acute intestinal infection plays an important role in the pathogenesis of irritable bowel syndrome （IBS）, and many researchers studied the pathogenesis of IBS by creating animal model of visceral hypersensitivity. But few observed the similarities and differences of evolution of visceral sensitivity after infection in different types of animal models.By comparing the similarities and differences of evolution of visceral sensitivity in mice and rats after intestinal infection, this study aimed to clarify that similar factors may lead to visceral hypersensitivity in different ways. Methods Mice and rats were infected with Trichinella spiralis. The weight of the mice and rats at 2 weeks and 8 weeks after infection were measured. Visceral sensitivity of colorectal distension in mice and rats were assessed by abdominal withdrawal reflex(AWR) at different time points before and after infection. Tissues of jejunum, terminal ileum, proximal colon and distal colon were collected after mice and rats were sacrificed. Histopathological changes and inflammation were assessed with HE staining. Results The weight growth rates of mice and rats at 2 weeks after infection were lower than that in the control group(P=0.021, 0.092, respectively). The weight growth rates of mice and rats at 8 weeks after infection had no significant differences as compared with control groups(P=0.596, 0.827, respectively). In both mice and rats, The intestinal pathologic scores in 2 weeks groups were higher than that in control groups; the 8 weeks groups recovered from the intestinal inflammation , and had no significant differences with control groups. At 40, 60 mmHg, in mice , the AWR scores of all the infectious groups were higher than that in the control group(at 40 mmHg, P=0.000, 0.010, respectively; at 60 mmHg, P=0.000, 0.014, respectively), and in 2 weeks group increased more significantly; In rats, the AWR scores of 2 weeks group was lower than that in control group(P=0.046, 0.035, respectively), and the AWR scores of 8 weeks group was much higher than that in control group(P=0.009, 0.000, respectively) and 2 weeks group(P=0.005, 0.001, respectively). Conclusion The intestinal inflammation in mice and rats subsided 8 weeks after Trichinella spiralis infection, visceral hypersensitivity remained; however, the processes of them were different. Therefore, similar intestinal inflammation may lead to visceral hypersensitivity in different ways.