Carbon Monoxide Ameliorates Dextran Sulfate Sodium(DSS)-induced Colitis Through Inhibition Of GSK3β Signaling

Objective:To observe the anti-inflammatory effects of carbon monoxide(CO) on dextran sulfate sodium(DSS) induced colitis via inhibiting GSK3β signaling.Methods:For in vivo experiments,50seven week-old male C57BL/6mice were seperated into two sets. Then25mice in each set were randomly assigned into five groups (Control, DSS, DSS+CO, DSS+LiCl, and CO groups). To construct acute colitis mouse model, we provided mice from DSS, DSS+CO and DSS+LiCl groups with3%DSS drinking water for six days. Then mice from CO and DSS+CO groups were inhaled250ppm CO gas for four hours each day and mice from DSS+LiCl group were performed intra-peritoneal injection of LiCl(200mg/kg) each day for another four to six days. For one set, survival rate were recorded until twelfth day. For another set, mice were sacrificed on tenth day, and were took out entire colon to perform histological and molecule assay. For in vitro and ex vivo experiments, we mainly cultured U937cell line and mesenteric lymph node(MLNs) cells as well as bone marrow macrophage(BMM) were isolated from mice. U937, MLNs, and BMMs were pretreated with CO-releasing molecules(CORM2) and lithium chloride LiCl for30minutes followed by stimulation of LPS for30minutes to check mRNA and protein level of pro-and anti-inflammatory mediators.Results:Our data showed that the inhalation of CO or pretreatment of CORM2in U937or MLN cells followed by stimulation of LPS inhibited the activation of GSK3β via increasing the phosphorylation of GSK3β at serine9residue. CO and CORM2also inactivated NF-kB, as well as inhibited the expression of TNFa and iNOS.Conclusion:Our results indicated that the effect of CO improved the pathological change of colitis induced by DSS, and also reported a novel effect of CO on inhibition of GSK3P signaling in DSS-induced colitis mice model.