| Background： It has been widely accepted that age is one of the major riskfactors in the occurrence and development of cardiovascular disease. Numerousstudies have shown that with the increase of age, cardiovascular structuralchanges, leading to changes in the cardiovascular function, resulting in theoccurrence of cardiovascular disease. MicroRNAs are a class of smallnon-coding RNA, which play a regulatory role in many physiological andpathological processes in the body, including cell differentiation, proliferation,apoptosis and the development and progression of many diseases. Recent studiesindicated microRNAs also involved in the regulation in aging process of thecardiovascular system.Objective: This study was designed to study the impact of age on thestructure and physiological function of cardiovascular system, and implicit thechanges of apoptosis-related proteins and the expression of mircoRNA-1,microRNA-133a during aging, providing scientific experimental datas thatverify the impact of aging process on the physiology and function ofcardiovascular system and that some related mircoRNAs involved in the agingheart.Methods: F344BN Rats of different months were divided into6-month group (n=8),26-month group (n=8) and30-month group (n=8). The weight ofall rats were weighed.Then electrocardiography was performed. The weight ofheart were weighed and the left ventricle were cut into two parts after the ratswere executed.Expression of Apoptosis-related proteins (Caspase-3、Bac-2、Bax、Akt et al) and microRNA-1, microRNA-133a in hearts was compared byWestern blot and qReal-Time PCR, respectively.Results: Compared with the6-month-old rats, the body weight and cardiacmass of26-month-old and30-month-old rats increased significantly (P<0.05).Compared with the6-month-old rats, the ratio of heart weight to body weight of30-month-old rats increased significantly (P <0.05).The thickness of left ventricular posterior wall of30-month-old group insystolic stage increased significantly compared to the6-month-old group (P<0.05). Compared with the6-month-old rats, EF and FS of30-month-old ratsdecreased significantly (P <0.05).Compared with the6-month-old rats, the content of total Caspase-3of26-month-old rats and30-month-old rats decreased by15.79%and25.28%respectively (P <0.05). Compared with the6-month-old rats,19kDa fragment ofCaspase-3of30-month-old rats increased by367.24%(P<0.05),17kDafragment of Caspase-3increased by225.94%(P <0.05), the content of Bax of30-month-old rats increased by36.48%, and the content of Bcl-2did not changeevidently in each group. Total Akt and phosphorylated Akt (Ser473) were notsignificantly different in each group. The expression of microRNA-1of30-month-old rats increased evidentlycompared to6-month-old rats and26-month-old rats (P <0.05). The expressionof microRNA-133a of30-month-old rats decreased significantly compared to6-month-old rats and26-month-old rats (P <0.05).Conclusion: The morphology of heart changed degeneratively, cardiacsystolic function decreased in aging rats. Apoptosis-related proteins inmyocardial tissue of aging rats changed significantly, indicating that apoptosisenhanced in the aging process of heart. MiRNA-1and miRNA-133a involved inthe aging process of cardiac apoptosis. |
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