| Objective: Based on the Janus kinase 2 /signal transducers and transcription activator 3(JAK2/STAT3)signaling pathway,the protective effect of the Dragon's blood on cardiomyocytes induced by ischemia-reperfusion injury in the New Zealand rabbits was investigated.Methods: To observe the protective effect of the Dragon's blood on the myocardial cell injury by myocardial ischemia-reperfusion in the New Zealand Rabbits,the model of myocardial ischemia-reperfusion injury was made by the anterior descending ligation and the experimental model animals were treated respectively with Dragon's Blood or Dragon's Blood+AG490(Tyrphostin Ag 490).40 New Zealand rabbits were random divided equally into four groups,such as control group,model group,Dragon's blood group and AG490 group(Dragon's blood intervention+ AG490 signal pathway blocker).After 7 days of adaptive feeding,the control group and the model group were intragastric administrated with 5ml normal saline once a day during 7 days while the Dragon's blood group and the AG490 group were intragastric administrated with the solution of the Dragon's blood(180mg·kg-1)and 5ml physiological saline solution.And the animals were fasting for 12 hours before surgery in the eighth day.The control group was only threaded without ligation while the other groups were ligated for 30 minutes,then cut and reperfused for 120 minutes.AG490 was used as the signal pathway blocker and the animals of AG490 group were injected in the marginal vein of ear with 3mg·kg-1 AG490 at 5 minutes before reperfusion.ECG was monitored and compared during the experimental process.At the same time,we measured the left ventricular systolic pressure(LVSP),the left ventricular end-diastolic blood pressure(LVEDP),the maximum rate of rise of left ventricular pressure(+dp/dtmax)and the maximum rate of descending of left ventricular pressure(-dp/dtmax)at the end of reperfusion.The lactate dehydrogenase(LDH)and the creatine kinase isoenzyme(CK-MB)were detected.Myocardial tissue was taken for the hematoxylin eosin(HE)staining and immunohistochemical sections and the optical density(OD)value of the p-JAK2 and the p-STAT3 protein expression can be calculated.The expression of JAK2 and STAT3 mRNA were detected by the real time-PCR(RT-PCR).All measurement data were treated as mean ± standard deviation(x ±s)and the One-Way ANOVA method was used for statistical analysis between groups.Different groups were compared with the SNK method and the difference was statistically significant when P is lower than 0.05.Results: 1.Comparison of the ECG: The control group showed normal ECG during the whole experimental process and the model group showed typical ECG manifestations of myocardial infarction.There was slight change between the T wave and ST segment of the ECG of the Dragon's blood group and the AG490 group.2.Comparison of the left ventricular LVSP,LVEDP,+dp/dtmax,-dp/dtmax: The LVSP and +dp/dtmax of the model group were lower than those of the control group while the LVEDP and-dp/dtmax were higher than those of the control group,and the difference was statistically significant(P<0.05).The LVSP and +dp/dtmax of the Dragon's blood group were lower than those of the control group while the-dp/dtmax was higher than the control group,and the difference was statistically significant(P<0.05).The LVSP and +dp/dtmax of the Dragon's blood group and the AG490 group were higher than those of the model group while the LVEDP and-dp/dtmax were lower than those of the model group,and the difference was statistically significant(P<0.05).The LVSP and +dp/dtmax of the AG490 group were higher than those of the Dragon's blood group while the-dp/dtmax were lower than those of the Dragon's blood group and the control group,and the difference was statistically significant(P<0.05).3.Comparison of the LDH and CK-MB enzymes: There is no significant difference(P=0.49)between different groups LDH.The CK-MB of the control group was lower than that of the Dragon's blood group and the model group,and the difference was statistically significant(P<0.05).The CK-MB of the Dragon's blood group and the AG490 group were lower than that of the model group,and the difference was statistically significant(P<0.05).To compare,there was no statistically significant between CK-MB of the control group and the AG490 group.4.Observation of the HE staining: The myocardial tissue in the control group was normal staining.The myocardial tissue in the model group was seriously damaged.The myocardial tissue in the Dragon's blood group was significantly better than that of the model group.The myocardial tissue in the AG490 group was significantly better than that of the model group,slightly better than that of the Dragon blood group and worse than that in the control group.5.Observation of the p-JAK2 and p-STAT3 in the immunohistochemical pathological sections: The p-JAK2 and p-STAT3 in the control group was stained with brownish yellow color.The staining of the model group and Dragon's blood group were deeper than that of the control group.There were similar color in the model group and the dragon's blood group.The p-JAK2 staining in the AG490 group was the deepest and showed strong positive reaction and the p-STAT3 staining in the AG490 group was the lowest.6.Comparison of the OD value of the p-JAK2 and p-STAT3 in the immunohistochemical pathology sections: The OD value of the p-JAK2 and p-STAT3 in the control group was lower than that in the model group and the Dragon's blood group,the difference was statistically significant(P<0.05);the OD value of the p-JAK2 in the AG490 group was higher than that in the control group,the model group and the Dragon's blood group,the difference was statistically significant(P <0.05);the OD value of the p-STAT3 in the AG490 group was lower than that in the model group and the Dragon's blood group,the difference was statistically significant(P <0.05).The OD value of p-STAT3 in AG490 group was not statistically different from that in control group.7.Comparison of mRNA amplification rates of the JAK2 and STAT3: The mRNA amplification rate of the JAK2 in model group and the AG490 group was higher than that in the control group and the Dragon's blood group,the difference was statistically significant(P <0.05);the mRNA amplification rate of the STAT3 in the model group was higher than that in the control group,the Dragon's blood group and the AG490 group,the difference was statistically significant(P <0.05).Conclusion: 1.The JAK2/STAT3 signaling pathway in the New Zealand rabbits was activated by ischemia-reperfusion injury.2.The Dragon's blood has the protective effect on myocardial ECG stability,the integrity of myocardial tissue anatomy and the left ventricular function,it can reduced the CK-MB in the New Zealand rabbits with ischemia-reperfusion injury,the protective effect is closely associated with the JAK2/STAT3 signaling pathway. |
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