| BACKGROUND：Heat shock proteins (Hsps)，due to its inhibition of stressenvironment of cell apoptosis, has become a focus of recent research athome and abroad. It is the highly conserved proteins, widespread and thecreatures in the nature. Hsps are divided into seven families accordingto their molecular weight and molecular structure: Hsp10，small Hsps，Hsp60，Hsp70，Hsp40，Hsp90，Hsp100.Heat shock protein27(Hsp27), is animportant member of the small Hsps. Hsp27has a low lever in normal cells.When the cells from oxidative stress injury, the expression level of Hsp27increased and exert its protective effect.At present, same experimental results suggest, Hsp27can protectorgans from the ischemia reperfusion injury. Other studies have found themain function of Hsp27:(1) Molecular chaperones function-Help theproteins in cells to correct folding and release.(2) Inhibition ofapoptosis under oxidative stress conditions and increase cell tolerance.(3)lowering the levels of reactive oxygen species (ROS) by raising levelsof intracellular glutathione and lowering the levels of intracellulariron.(4) Involved in the cellular immune response, reduce inflammatoryinfiltration.In cardiovascular disease, someone identified Hsp27as a potentialbiomarker of atherosclerosis amongst a cohort of differentiallysecreted proteins. They found Hsp27expression to be decreased inatherosclerotic plaques with normal expression in healthy arteries. Atthe same time,others confirmed that during atherosclerosis, HSP27isdown-regulated in the most severe plaques or the plaque core, while normaladjacent tissue expressed higher levels of Hsp27. Hsp27has been implicated in atherosclerosis disease as a potential biomarker of diseaseand injury.This Experiment use hydrogen peroxide (H2O2) to handle rat myocardialcells (H9C2cells) resulting in oxidative stress injury. By changing thehydrogen peroxide concentration and treatment time, causing differentdegrees of damage. Testing the expression of Hsp27mRNA by the method ofRQ-PCR determination, to do the evaluation whether there is a linearrelationship between the amount of myocardial cell Hsp27expression andthe degree of cell damage assessment. Further confirmed the role of Hsp27in the process of myocardial oxidative injury and its mechanism.OBJECTIVE: Use hydrogen peroxide (H2O2) to handle rat myocardial cells(H9C2cells) resulting in different degrees of oxidative stress injury.Study on the expression and mechanism of rat myocardial cells’ Hsp27after oxidative stress injury.METHOD:1. Cell viability was determined by MTT assays.2. The expression of Hsp27m RNA and Bax m RNA was determined by themethod of qRT-PCR determination.3. Statistical analysis.RESULT:1.MTT’s result show that significantly inhibits H9C2cells growthat different concentrations of H2O2（0.05mmol/l,0.1mmol/l,0.5mmol/l,1mmol/l,5mmol/l）, and induces cell apoptosis. At the same time，the timeextension, the survival rate decreased.2. Detection of RQ-PCR gene expression:When the degree of cellular oxidative stress is light, compared withthe control group, the expression of Hsp27mRNA increased obviously(P<0.05), while the Bax mRNA expression was slightly reduced (P<0.05),whit the damage degree increases further, the expression level ofHsp27mRNA began to decrease (P<0.05), while the Bax mRNA expression was significantly increased (P<0.05).3．The data obtained by SPSS17.0detection, there was statisticalsignificance.CONCLUSION:1. Different time of H9C2cells treated with different concentrationsof H2O2application, can cause different degree of myocardial cellapoptosis.2. The expression of Hsp27is associated with the degree of the stressand oxidation of cells, light degree of oxidative stress, Hsp27expressionincreased, and can resist oxidative stress. WIth the degree increased,the expression of Hsp27begun to decrease, unable to resist the oxidativestress, triggering apoptosis program. |
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