The Protection Of Heat Shock Protein 22 In The Ischemia-reperfusion Damage Of Cardiac Muscle

Background and Purpose:Heat shock proteins (Heat Shock Proteins, HSPs) are a group of paticular proteins produced by the heat shock genes triggered when the organisms under situations of special physical, chemical or microbial stress. They can quickly adjust cells'survival function during the stress process, protect cells against damages and help the recovery of nomal cellular structure and function. Myocardial ischemia-reperfusion injury (Myocardial Ischemia/Reperfusion Injury, MIRI) usually happens when the myocardial cells with reversible ischemic injury get the blood supply is restored again. All the protective mechanisms are related with the induced generation of heat shock protein. In this paper,the mouse model with overexpression of HSP22 is used, to study the function of HSP22 and to clarify the protection mechanism of HSP22 in myocardial ischemia /reperfusion injury. All these works are the basis to develop the drugs which can reduce heart attacks and prevent myocardial diseaseMethods:DNA was extracted from tails of F4 generation transgenic mice, while the founder mice were confirmed by PCR, sequencing and Southern Blot analysis. The transgenic mice of HSP22 were identified by PCR and sequencing. Myocardial ischemia-reperfusion injury model was produced with wild-type C57BL mice(the control group,n=5) and pCAGGS-HA-HSP22 transgenic C57BL mice(the experimental group,n=5), the body weights and ages were no significant difference. The content of HSP22 protein in the mice myocardium were measured by the immunohistochemistry, which the concentration of malondialdehyde (MDA) and protein carboxyl were measured by direct chemical method after ischemia/reperfusion. The results were analyzed to compare whether there was significant difference between HSP22 protein content, malondialdehyde (MDA) and protein carboxyl concentration in two groups of myocardial tissue.Then we analyze whether there was a protectional function of HSP22 protein on ischemia/reperfusion injuryResults:1. Transgenic mice of overexpression of HSP22 was successfully identified by transgenic mice with human wild-type HSP22 gene passaged to F3/F4 through the method of sequencing the mice tail DNA2. The expression of HSP22 protein existed in cardiac tissue of myocardial ischemia reperfusion injury models of two grpups. Proteins were mainly expressed in the cytoplasm. PI value (10.21±4.75) of the experimental group is significantly higher than PI value of the control group (4.19±1.12), which was significantly different (P＜0.05).3. Detection results of MDA of two groups miceThe results suggest that the content of MDA (193.89±27.61) in the control group was significantly higher than that in the experimental group (82.96±29.14), which was significant different (P<0.05).4. Detection results of protein carbonyl of two groups miceThe results suggest that the content of protein carbonyl (21.56±9.12) in the control group was significantly higher than that in the experimental group(6.56±1.99), which was significant different (P<0.05).Conclusion:1. Transgenic mice with human wild-type HSP22 gene can stably passage in F3,F4 generation mice.2. HSP22 expression in cardiac tissue of the experimental group which modeled by myocardial ischemia reperfusion injury was significantly higher than that in the control group.3. HSP22 produces a protective function in myocardial ischemia-reperfusion injury by reducing lipid peroxidation and protein peroxidation in the myocardial.