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AIM: To evaluate the role of stress（early-life stress and acute sterss） on intestinal mucosal inflammation and visceral sensitivity in rats.METHODS:Thirty-six newborn male Sprague-Dawley（SD） rats were randomly divided into control group（CON,n=12）, maternal separation group（MS,n=12） and acute water avoidance group（WA,n=12）. The newborn rats in MS were recepted maternal separation between 2nd -21st day postnatal . The rats in WA were recepted a water avoidance at the 60th day. At the 2nd month, abdominal withdrawal reflex （AWR） and myoelectric amplitude （MA） of the oblique externus abdominis muscle were recorded respectively after colonic distention. The colonic tissue samples were collectted for histopathologic examinations and toluidine blue stain, and the contents of IL-1βand tryptase in colon tissue culture supernants were dected by ELISA.RESULT:The mean mucosal inflammation score in MS（1.60±0.52） was ,significantly higher than in WA（0.60±0.70,P=0.000） and in CON（0.50±0.53,P=0.000）.The mast cell numbers in MS（6.97±1.12,cells/HPF） were significantly higher than that in WA（3.79±0.53,P=0.000） and in CON（3.76±0.61,P=0.000） respectively. The content of IL-1βin MS was 22.72±2.63pg/g,significantly higher than in WA （13.96±1.34 pg/g,P=0.001） and CON（13.94±1.71 pg/g,P=0.000）. The content of tryptase in MS was 2.99±0.37ng/g,that’s significantly higher than in WA（1.66±0.27 ng/g,P=0.000） and CON （1.66±0.33 ng/g,P=0.000）.When the balloon pressure was up to 40, 60, 80mmHg respectively, the AWR score and MA in MS and WA were significantly higher than those in CON（all P < 0.05）, and these indexes were positively correlated with the mucosal inflammation（P<0.05,respectively ）.CONLUSIONS:The stress（including early-life stress and acute sterss） may activate the visceral sensitivity, and the arly-life stress may induce low grade mucosal inflammation in the colon which may activate the visceral sensitivity.
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