Abstract: Objective To investigate the expression of β-catenin in the intestinal mucosa of rats with severe abdominal infection.Methods Forty healthy adult Wistar rats were randomly divided into a control group(n=10,with celiotomy only)and 3 abdominal infection groups(n=10)sacrificed at 12,24,48 h after cecal ligation plus puncture for inducing severe abdominal infection,respectively.Immunohistochemistry and RT-PCR were performed to detect β-catenin expression in the crypt of the small intestine during severe abdominal infection and in normal conditions.Results Rats with severe abdominal infection showed stronger β-catenin expression in the crypt of the small intestine than normal rats,and the transcription level of β-catenin was associated with the stages of severe abdominal infection.RT-PCR showed that β-catenin mRNA increased rapidly 12 h after the infection(0.74±0.10 vs 0.52±0.06,P<0.01),reaching the peak level at 24 h(0.90±0.09,P<0.01),followed then by gradual decrease but remained still obviously higher than the control level at 24 h(0.80±0.09,P<0.01).Conclusions Severe abdominal infection may induce β-catenin expression which might be related with the proliferation and differentiation of intestinal stem cells in such condition and play an important role in intestinal mucosa damage and repair.