The Effect Of ?2-glycoprotein ? On Rat Myocardium Ischemia/Reperfusion Injury

BackgroundCoronary heart disease is a common challenge in the fields of cardiovascular and diabetes.Myocardial ischemia/reperfusion(I/R)injury is the main cause of death after coronary artery recanalization surgery.The pathological mechanism of myocardial I/R injury is very complex.Reactive oxygen species(ROS)damage(oxidative stress)and apoptosis are two important factors for I/R injury.?2-glycoprotein I(?2GPI)is a kind of plasma protein.It has two forms:oxidized form and reduced form.Recent studies have revealed?2GPI and reduced?2GPI reduced nitric oxide-induced cell injury and apoptosis,and alleviated intestine I/R injury in mice.ObjectiveObjective:To evaluate the impact of?2GPI and reduced?2GPI on myocardial I/R injury,and explore its mechanisms;to observate and compare the difference between?2GPI and reduced?2GPI in the impact on myocardial I/R injury.Method(1)Animal experiments:acute myocardial I/R injury model was establish using SD rat.?2GPI or reduced?2GPI was administered by tail vein injection pre-ischemic.Following indicators was explored to evaluate the effect of?2GPI and reduced?2GPI on myocardial I/R injury:1)cardiac function indicators:LVSP,LVEDP,±LVd P/dt_max;2)myocardial injury indicators,including:infarct size(TTC staining),cardiac morphology(HE staining),serum CK-MB and c Tn I levels(ELISA);3)oxidative stress indicators:reductase activity and MDA content;4)apoptosis:apoptosis index(TUNEL),caspase 3 activity,bcl-2/bax m RNA ratio(real-time PCR),mitochondrial cytochrome c(cytochrome c,cyt c)content in cytosolic and mitochondrial(Westerm blot).(2)Cell experiments:three-gas-incubator was used to establish H9c2 hypoxia/reoxygenation(H/R)injury model.Following indicators was explored to evaluate the effect of?2GPI and reduced?2GPI on H9c2 H/R injury and its mechanism:1)cell viability(MTT);2)LDH level;3)ROS level(DCFH-DA probe);4)apoptosis,including:apoptosis rate(Annexin V/PI double staining),mitochondrial membrane potential(JC-1 staining),caspase 3 activity,bcl-2/bax m RNA ratio;5)signaling pathway:protein expression and phosphorylation of Akt/GSK-3?(Western blot).Result(1)Animal experiments:1)cardiac function:two types of?2GPI improved the cardiac function to some extent;2)myocardial injury:after two types?2GPI pretreatment,the infarct size decreased significantly(TTC staining),the myocardial morphology was improved(HE staining),the levels of serum CK-MB and c Tn I were also significantly reduced(ELISA);3)oxidative stress:reduced?2GPI inhibited XOD activity significantly;two types of?2GPI significantly reduced the production of MDA;4)apoptosis:two types of?2GPI significantly reduced apoptosis index(TUNEL),caspase 3 activity and cyt c(cytosol/mitochondria)ratio,increased m RNA ratio of bcl-2/bax.Compared with?2GPI,in apoptotic index,XOD activity and MDA content indicators,reduced?2GPI played a stronger role;on the other indicators,it showed a trend that reduced?2GPI had a stronger effect than?2GPI,but the difference was not statistically significant.(2)Cell experiments:1)two types of?2GPI significantly increased cell viability(MTT);2)cell injury:two types of?2GPI improved cell morphology,and significantly decreased LDH levels;3)oxidative stress:two types of?2GPI significantly reduced H/R-induced ROS production(DCFH method);4)apoptosis:two types of?2GPI stabilized mitochondrial membrane potential(JC-1 staining),increased m RNA ratio of bcl-2/bax,inhibit H/R-induced apoptosis(Annexin V/PI double staining);5)signaling pathway:two types of?2GPI significantly increased the phosphorylation of Akt and GSK-3?.6)Compared with?2GPI,in ROS level and bcl-2/bax ratio indicators,reduced?2GPI played a stronger role;on the other indicators,it showed a trend that reduced?2GPI had a stronger effect than?2GPI,but the difference was not statistically significant.Conclusion(1)?2GPI and reduced?2GPI can alleviate oxidative stress,inhibit mitochondrial apoptotic pathway and activate Akt/GSK-3?signaling pathway,finally reduce myocardial I/R(H/R)injury in SD rats.(2)In general,reduced?2GPI has a stronger protective effect on myocardial I/R(H/R)injury than?2GPI.