Preventive effect and mechanism of exogenous bilirubin on cerebral ischemia reperfusion injury in rats
Objective:To study the effect of exogenous bilirubin on cerebral ischemia reperfusion injury(I/R)and apoptosis.Methods:SD rats were selected and randomly divided into Sham group(Sham group),modeling group(I/R group),5 mg/kg bilirubin group(I/R+5 mg group),10 mg/kg bilirubin group(I/R+10 mg group),and 15 mg/kg bilirubin group(I/R+15 mg group).The rats were given medicine for seven days before modeling.The plugging filament method was used to establish the rats'cerebral ischemia-reperfusion injury model.24 h after the modeling was completed,specimens were taken for measurement.The infarct volume was determined by triphenyl tetrazolium chloride staining.Pathological changes of cerebral infarction area were observed by H-E staining.TUNEL staining was used to detect the apoptotic cells and immunofluorescence histochemistry was used to detect the positive cells of p-caspase 3 in the brain tissue.Results:Compared with the I/R group,the infarct size of the I/R+10 mg group was significantly reduced.Brain morphology of the I/R+5 mg and I/R+10 mg groups was more normal compared with the modeling group.Compared with the I/R group,the number of TUNEL-positive cells in the brain tissue of the I/R+10 mg group was significantly reduced,and the number of p-caspase 3 positive cells in the brain tissue of I/R+5 mg,I/R+10 mg,and I/R+15 mg groups was significantly reduced.Conclusions:Exogenous bilirubin can prevent cerebral ischemia-reperfusion injury in rats within a certain dose range,and its protective mechanism is related to the inhibition of apoptosis.