Study Of Relationship Between Status Of P53Gene Promoter Methylation And Ischemic Stroke

Research background and objective:Stroke is one of the diseases with high prevalence, mortality and morbidity, which together with heart disease, malignant tumors contribute to the top three causes of deaths, and as high as75%of the survivals are disabled. In recent years, the epidemiological data of our country shows that stroke has been the second cause of death only second to malignant tumor. Ischemic stroke, which is also called cerebral infarction, contributes to60-80%of the stroke. There are many independent risk factors of the disease, and its pathogenesis is complex. Exploring the pathogenesis of ischemic stroke is helpful to choose the appropriate treatment, and to enhance the curative effect and reduce the occurrence of complications and reduce the incidence of ischemic stroke and the recurrence rate.Epigenetic refers to changes of gene expression with the same gene sequence. It is one of the body’s normal development organization mechanisms, and its changes can cause abnormal genetic functions. Because of its adjustment mechanism is reversible, which provides new ideas for the treatment of disease. In recent years, the epigenetic mechanism of the onset of ischemic stroke becomes the new research direction. For now, DNA methylation has been an important part of epigenetic and epigenomics. Studies show that DNA methylation is related to many diseases. In recent years, many studies have been reported about epigenetic in cardiovascular disease, but fewer articles about DNA methylation and stroke. It’s not clear about the relationship between DNA methylation and stroke. This study was designed to investigate the alteration about methylation patterns of p53gene promoter in ischemic stroke patients, and discuss the relationship between p53gene promoter methylation and ischemic stroke.Objects and methods:78patients were enrolled in this study, recruited from October,2010to February,2011in the Second Hospital of Shandong University. All of the case group patients accorded with cerebrovascular disease diagnosis standard of the4th cerebrovascular disease meeting in1995, were confirmed for cerebral infarction by MRI or CT.86people without cerebral vascular disease served as the control group, which with no cerebral infarction in evidence, and/or head CT/MRI is normal. The two groups matched on both age and gender, which are comparable.All participants were supposed to be taken fasting blood sample, extracting DNA genome. The methylation status of P53gene promoter was measured by methylation specific PCR (MSP) method, and the results of MSP were verified by bisulfate sequencing PCR(BSP).Results:1. The p53gene promoter methylation frequencies of the study group and control group were32.1%(25/78)、16.3%(14/86), with significant difference between any two groups (P<0.05).2. The P53gene promoter methylation frequencies of two age subgroups in ischemic stroke group were27%(10/37)、36.6%(15/41). And the methylation frequencies of age subgroups in control group were14.7%(5/34)、17.3%(9/51).The methylation frequency tended to increase with age in both groups, but there was no statistical significance (P>0.05).3. The HCY level of ischemic stroke group was analyzed, the means of25cases of the methylation group was33.91±23.81μM,while the unmethylation group was23.19±5.67μM, with significant difference between any two groups (P=0.004).4. There are38cases of ischemic stroke patients who had undergone carotid colorized ultrasound examination. The carotid intima-media thickness(CIMT) were recorded, the means of19cases of the methylation group was1.06±0.35(mm), while the unmethylation group was0.87±0.19(mm), with significant difference between any two groups (P<0.05). Compare Crouse score of different groups, the means of19cases of the methylation group was4.97±4.40, while the unmethylation group was2.82±2.80, with significant difference between any two groups (P<0.05).5. The MRA examination results of65patients were recorded. Compare the methylation frequency of the four subgroups, there was no statistical significance (P>0.05).6. The methylation frequencies of three infarct size subgroups were compared, and there was no statistical significance (P>0.05).7. The result had been proved using BSP method that An significantly higher methylation degree in promoter region of p53gene promoter was found in peripheral blood genome of ischemic stroke patients.Conclusion:An significantly higher methylation degree in promoter region of p53gene promoter was found in peripheral blood genome of ischemic stroke patients compared with the controlled healthy subjects. The P53methylation degree was related with the carotid artery atherosclerosis level and HCY concentration of peripheral blood We don’t observe the relationship between p53gene promoter methylation and age, and the methylation status is not related to the infarct size and the severity of intracranial aitherosclerosis.