Abstract: 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.

Key words: trichinella spiralis, visceral sensitivity, animal model