The Expression Of Angiotensin Ⅱ-aldosterone In Radiation-induced Heart Disease

IntroductionAngiotensinⅡ(AngⅡ)and aldosterone are the key constituents of the renin-angiotensin-aldosterone-system and play an important pathophysiological role in cardiovascular disease.Synthesis of aldosterone,angiotensinⅡand ACE will increase when there is trouble in hearts.On the other hand,the manifestations of Radiation-induced heart disease(RIHD)usually may include acute/chronic pericarditis, accelerated atherosclerosis(such as coronary artery disease),conduction abnormalities, valvular changes,and,notably,pericardial and myocardial fibrosis.The patho-physiology of RIHD is similar to that induced by angiotensin-aldosterone. Sprague-Dawley rats were irradiated with a single dose of 0,15 or 18 Gy locally to the heart.3 months after irradiation,mRNA expression of AT1 and ACE in heart tissue was determined by using the RT-PCR,the concentrations of angiotensinⅡand aldosterone were determined by using ELISA.The expression level of angiotensinⅡ-aldosterone in radiation-induced heart disease will be discussed in this study,and the patho-physiological effect of angiotensinⅡ-aldosterone in the progress of radiation-induced heart disease will also be analysed.Materials and Methods一.Tissue SamplesSprague-Dawley rats(3 months old,180-220g,male=female,from the animal centre of China Medical University)were excuted by over-anaesthetization with 3.6%chloral hydrate 3 months after intervention.The heart tissue was excised and stored in refrigerator at the temperature of -85℃.二.Reagents RT-PCR agent kit was purchased from Takara biotechnology(dalian)co.Ltd. Animal RNAout agent was purchased from Tiandz company in Minyang gao xin qu. AngiotensinⅡand aldosterone ELISA assay kits were purchased from RapidBio Lab.三.MethodsSprague-Dawley rats were irradiated with a single dose of 0,15 or 18 Gy locally to the heart.3 months after irradiation,mRNA expression of AT1 and ACE in heart tissue was determined by using the RT-PCR,the concentrations of angiotensinⅡand aldosterone were determined by using ELISA.SPSS13.0 statistical software was applied for data analysis.Results are expressed as means±SE.Data were analyzed by one-way ANOVA and differences between groups were determined by LSD t-test if equal variances was met.If equal variances was not met,nonparametric test was followed.Differences were considered statistically significant at a value of P＜0.05.ResultsThere was statistical difference of mRNA expression of AT1,ACE,angiotensinⅡand aldosterone between non-irradiation group and irradiation groups,the p values were 0.032,0.006(AT1);0.004,＜0.001(ACE);＜0.001,0.009(angiotensinⅡ);0.008, 0.007(aldosterone),separately.No differences of AT1,ACE,angiotensinⅡand aldosterone were detected between the two irradiation groups,the P values were＞0.05,separately.Conclusions1.AngiotensinⅡ-aldosterone plays an important pathophysiological role in the progress of radiation-induced heart disease.What's more,as the radiation doses rise, the impacts of angiotensinⅡ-aldosterone on radiation-induced heart disease may be stronger.2.No differences of AT1,ACE,angiotensinⅡand aldosterone were detected between the two irradiation groups,,probably duing to small samples,or the different irradiation doses,or the different duration after irradiation,all of which need to deeply study.