| Objective: To investigate the expression level of cardiac hypertrophy associated proteins and the histone deacetylases 5(HDAC5)-mediated acetylation of Histone H3K27 ac in stress-induced heart failure in mice.Methods: SPF grade healthy Kunming mice of 6 to 8 weeks were selected for the study.Thoracic aortic constriction(TAC)model group and Sham group were divided by the principle of random digit method.In the TAC group,The samples were collected at 4weeks,8 weeks and 12 weeks.There were 6 mice in each group.In the TAC group,partial ligation of the aortic arch was performed at a level approximately 70% of the diameter of the aortic arch.In the sham group,only aortic arch separation was performed without subsequent aortic arch ligation,and other surgical procedures were the same as in the TAC group.The hearts of mice 4,8 and 12 weeks after surgery were collected for the following tests:(1)Color Doppler was used to detect the thickness of left ventricular cavity and wall,and ultrasonographic Doppler was used to observe the blood flow at the ligation site;(2)Lung mass index(LMI)and cardiac mass index(CMI)of the mice were measured.(3)The appearance of mouse heart was observed by stereoscopic microscopy,and the changes of heart morphology and cardiomyocyte morphology were observed by htoxylin eosin(HE)and Masson’s trichrome(Masson)staining.(4)Western blot was used to detect HDAC5,histone H3K27 ac and the protein expressions of ANP and BNP.Results:(1)Echocardiography data clearly showed that the ligation site between the innominate artery,the left carotid artery,and the ligated aortic arch,was clearly constricted.Color Doppler imaging showed that poor blood flow to the aortic arch.(2)The stereoscopic results showed that the hearts of TAC mice at 4 weeks,8 weeks,and 12 weeks,were enlarged gradually when compared to the sham group.(3)Compared with Sham group,CMI of mice in TAC group was increased(P < 0.05),while LMI of mice in TAC group was not changed compared with Sham group(P > 0.05).(4)H&E staining results showed that the hearts in the TAC group were larger than those in the sham group at 4,8 and 12 weeks.Masson staining further demonstrated myocardial interstitial fibrosis and collagen accumulation in TAC mice.Myocardial fibrosis gradually increased at 4-12 weeks after modeling,and collagen deposition gradually increased at the same time.(5)The cardiac ultrasound showed that the left ventricular wall of mice in the TAC group was firstly thickened and then thinned 4 to 12 weeks after modeling,while there was no histological change in the sham operation group,and EF was also firstly compensated and then decreased.(6)Western blot results showed that histone H3K27 ac acetylation level in TAC group compared with sham group was firstly increased and then decreased(P < 0.05),while HDAC5 was gradually increased in TAC group from 4 to 12 weeks.The protein expressions of ANP and BNP were also increased first and then decreased(P < 0.05).Conclusions:HDAC5-mediated hypoacetylation of histone H3K27 ac in heart failure model mice induced by partial ligation of thoracic aorta may be related to the abnormal expression of ANP and BNP markers of cardiac hypertrophy.Objective: To investigate the effect of histone deacetylases(HDACs)inhibitor epigallocatechin gallate(EGCG)on histone deacetylation in heart failure induced by stress overload in mice.Methods: SPF grade healthy Kunming mice of 6 to 8 weeks were selected as the experimental subjects,and Kunming mice were divided into TAC + EGCG group,Thoracic aortic constriction(TAC)group,Normal group,Sham operation group,and Vehicle group by random number method.partial thoracic aorta(approximately 70% of thoracic aorta diameter)in the TAC group was ligated until 12 weeks postoperatively.In TAC + EGCG group,EGCG(50mg/kg/day)was intraperitoneally injected 1 week after thoracic aortic coarction,once a day until 12 weeks after surgery.The thoracic aorta in the sham operation group were only separated without ligation.Solvent control group is normal mice given equivalent dose equivalent number by intraperitoneal injection of EGCG to 12 weeks,12 weeks after modeling collect groups of mice under the myocardial tissue of inspection:(1)The left ventricular end diastolic dimension(LVEDD),left ventricular anterior wall thickness(LVAWT)and intervencicular septum(IVS)were measured by ultrasound at the end of diastolic and systolic period.Left ventricular end systolic dimension(LVESD)and left ventricular volume(LVV)and Left ventricular ejection fraction(LVEF)was measured.(2)Htoxylin Eosin(HE),Masson’s Trichrome(Masson)and Wheat Gerglutinin(WGA)staining were used to observe the morphology of heart and myocardial cells in mice.(3)The regulation of core transcription factor MEF2 A and cardiac hypertrophy genes ANP and BNP was detected by Ch IP-Q-PCR.(4)Western blot was used to detect H3K27 ac acetylation level,HDAC5 and protein expression of ANP and BNP.(5)The m RNA expression of the core transcription factor MEF2 A was detected by real-time polymerase chain reaction(Real-time PCR).(6)Co IP detected the interaction between HDAC5 and MEF2 A and H3K27 ac.(7)BL-420 s Biological Information Acquisition System was used to measure the left ventricular pressure in the heart of mice.Results:(1)Color ultrasound results of the heart showed that the LVESD and LVEDD in operation group were higher compare with Sham group,and EGCG could reduce the increase of LVEDD and LVESD in the heart of mice compared with TAC +EGCG group,with statistical significance(P < 0.05).However,there was no statistical between Vehicle and TAC group(P > 0.05).(2)The HE,WGA and Masson staining,according to the results of TAC group compared with control,increase cardiac size and surface area of myocardial cells in mice,TAC+EGCG group a TAC mice heart size and myocardial cell surface area significantly decreased(P < 0.05).Above result were not significantly changed in the Sham group compared with the Normal group(P > 0.05).(3)The results of Ch IP-Q-PCR indicated that the heart core transcription factor MEF2 A could bind to the ANP and BNP promoter regions in mouse myocardial tissue.(4)Western blot results showed that H3K27 ac in TAC group was lower than that in Sham group.EGCG reversed the hypoacetylation of H3K27 ac in the heart of TAC mice compared with the TAC group(P < 0.05).At the same time,EGCG treatment could reduce the overexpression of HDAC5 in TAC mice(P < 0.05),and the protein expressions of ANP and BNP in TAC + EGCG group were higher than that in TAC group(P < 0.05).(5)R-T PCR results showed that the expression of MEF2 A m RNA in TAC group was decreased compared with that in sham group(P < 0.05),while EGCG treatment could up-regulate the MEF2 A in TAC mice(P > 0.05).(6)Co IP results show that HDAC5 can be combined with H3K27 ac and MEF2 A.(7)The results of carotid artery intubation showed that the left ventricular pressure in the TAC group was lower than that in the Sham group,and the left ventricular pressure in the EGCG group was higher than that in the TAC group(P < 0.05).Conclusions:(1)HDAC5-mediated hypoacetylation of histone H3K27 ac is involved in stress overload-induced heart failure in mice.(2)The HDAC inhibitor EGCG can regulate the expression levels of cardiac hypertrophy related genes ANP and BNP by inhibiting the hyperacetylation of histone H3K27 ac mediated by HDAC5,thus attenuating heart failure induced by stress overload in mice. |
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