Role of PI3K/Akt signaling in the protective effect of magnesium sulfate against ischemia-perfusion injury of small intestine in rats

Background The protective effects of magnesium sulfate against ischemia-reperfusion injury of the small intestine in Sprague-Dawley （SD） rats have been confirmed in our previous research. However, its exact mechanism is unclear. This study was to evaluate the role of PI3K/Akt signal pathway in the protective effect of magnesium sulfate against ischemia-reperfusion injury of the small intestine in SD rats. Methods Rat model of intestinal ischemia-reperfusion injury was used. The SD rats were divided into four groups randomly： sham operation group, ischemia-reperfusion group, magnesium sulfate group and magnesium sulfate plus LY294002 （an inhibitor of PI3K） group. The pathological changes of intestinal mucosa were examined; the activity of diamine oxidase （DAO） in plasma, the plasma contents of malondialdehyde （MDA）, and apoptosis rate of the intestinal mucosal cells were determined and compared. The expression of p-Akt was detected by Western blotting. Results There were more evident pathological changes of the intestinal mucosa （higher Chiu＇s score, P 〈0.05）, enhanced DAO activity （P 〈0.05）, elevated contents of MDA （P 〈0.05）, higher apoptosis rate （P 〈0.05）, and lower level of p-Akt （P 〈0.05） in the ischemia-reperfusion group compared with the sham operation group. There were less evident pathological changes of the intestinal mucosa （lower Chiu＇s score, P 〈0.05）, lower DAO activity （P 〈0.05）, lower contents of MDA （P 〈0.05）, and lower apoptosis rate （P 〈0.05）, but higher level of p-Akt （P 〈0.05） irL the magnesium sulfate group compared with the ischemia-reperfusion group. There were more evident pathological changes of the intes,inal mucosa （higher Chiu＇s score, P 〈0.05）, higher contents of MDA （P 〈0.05）, higher DAO activity （P 〈0.05） and higher apoptosis rate （P 〈0.05）, and lower level of p-Akt （P 〈0.05） in the magnesium sulfate plus LY294002 group compared with the magnesium sulfate group. Conclusions Activation of PI3K/Akt signal pathway results in the reduction of cell apoptosis, which likely accounts for the protective effect of magnesium sulfate against intestinal ischemia-reperfusion injury.