| Objective: Through continuous intravenous pump injection of dexmedetomidine during the cardiopulmonary bypass of pigs,the protective effect and mechanism of dexmedetomidine on the intestinal ischemia-reperfusion injury caused by cardiopulmonary bypass were studied.Methods: Nine healthy and clean piglets were randomly divided into normal control group(group A),cardiopulmonary bypass group(group B),cardiopulmonary bypass + dexmedetomidine group(group C),three heads per group.In group A,the chest was opened after general anesthesia without extracorporeal circulation.Groups B and C underwent cardiopulmonary bypass on the basis of group A.When the pig’s heart stopped beating for 1 hour,we gradually promoted its heart to return to beating.When the rebound time reached 2 hours,the pigs were killed by rapid bloodletting through the aorta,then the abdominal cavity was opened and the ileum tissue was collected to make a specimen.When the pig’s heart stopped beating for 1 hour,we gradually promoted its heart to return to beating.When the heart beats for 2 hours,we can quickly bleed through the aorta to kill the pig,then open its abdominal cavity and collect ileal tissue to make a specimen.During the operation,blood samples of each group were collected via arteries.We need to divide the intestinal tissue samples into two equal parts,and store them in a refrigerator at-80℃ and internal fixation with a concentration of2.5% glutaraldehyde.Then detect the concentration of D-lactic acid in the serum and the activity of diamine oxidase(DAO),the concentration of tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)in the intestinal tissue;the changes in the mitochondrial structure of intestinal endothelial cells were observed under an electron microscope.Results:Compared with group A,the concentration of D-lactic acid and the activity of DAO in the serum of groups B and C increased(P<0.05),the range of change in group B was higher than that of group C(P<0.05).The concentrations of TNF-α and IL-6 in the intestinal tissues of groups B and C increased more than group A(P<0.05),the increase trend of group C was lower than that of group B(P<0.05).Under the electron microscope,the mitochondria of intestinal endothelial cells in groups B and C were obviously damaged,and the damage in group B was heavier than group C.Conclusion: Dexmedetomidine can inhibit the inflammatory response of intestinal tissue during cardiopulmonary bypass injury and protect the intestine through mitochondrial protection and other ways. |
