OBJECTIVETo study the effect of Trichinella spiralis (T.spiralis) infection on the expression and distribution of colonic epithelial E-cadherin in mice and its mechanism.

METHODSBALB/c mice and STAT6-/- mice were infected with T.spiralis, and mice without infection were used as control. Seven days later, the horseradish peroxidase (HRP) was infused by rectal enema. Serum HRP was detected in the subsequent 0, 60 and 120 minutes. Then the mice were sacrificed and colon was taken out. The distribution of E-cadherin in colon was detected by immunofluorescence staining, and the expression of E-cadherin was detected by Western blot. The expression of interleukin-4 (IL-4) in mesenteric lymph nodes was detected by ELISA.

RESULTSSerum HRP level in infected BALB/c mice was significantly higher than that in control mice (P<0.05), while it was not significantly different between infected STAT6-/- mice and controls (P>0.05). In infected BALB/c mice, E-cadherin located in cytoplasm of colonic epithelial cells, while in controls, it located in cellular membrane. E-cadherin expression down-regulated significantly in infected BALB/c mice as compared to controls. E-cadherin expression and distribution did not change obviously in infected STAT6-/- and control mice. IL-4 level in mesenteric lymph nodes of infected BALB/c mice [(193.0±12.5) μg/L] was significantly higher as compared to control BALB/c and infected STAT6-/- mice [(21.0±2.3) μg/L and (15.0±3.1) μg/L, all P<0.05].

CONCLUSIONT.spiralis infection can increase colonic epithelial permeability of mice, which may be associated with induction of Th2 cytokine secretion.