有氧运动对老年自发性高血压大鼠心肌纤维化的影响

Effect of Aerobic Exercise on Myocardial Fibrosis in Aged Spontaneously Hypertensive Rats

目的:探讨有氧运动对老年自发性高血压(SHR)大鼠心肌纤维化的影响及其可能的基质金属蛋白酶表达机制。方法:12只16月龄雄性SHR大鼠随机分为安静组(SHR-SED)和运动组(SHR-EX),另选用12只同龄雄性WKY大鼠随机分为安静组(WKY-SED)和运动组(WKY-EX)。SHR-EX组和WKY-EX组进行8周有氧运动,坡度0°,20 m/min,60 min/day,5 d/周。8周后,测量各组大鼠血压、全心质量指数、心肌组织中胶原蛋白的表达以及基质金属蛋白酶-9和基质金属蛋白酶组织抑制剂-1的表达情况。结果:1)SHR-SED组大鼠收缩压显著高于WKY-SED组,SHR-EX组和WKY-EX组的收缩压分别显著低于SHRSED组和WKY-SED组;2)SHR-SED组全心质量指数显著高于WKY-SED组,SHR-EX组显著低于SHRSED组;3)SHR-SED组相比于WKY-SED组心肌胶原容积分数、Ⅰ、Ⅲ型胶原表达显著升高,SHR-EX组相比于SHR-SED组显著降低;4)SHR-SED组相比于WKY-SED组MMP-9以及MMP-1/TIMP-1显著升高,SHE-EX组相比于SHR-SED组显著降低。结论:老年SHR大鼠心肌呈现明显纤维化,其中MMP-9与TIMP-1的表达平衡是其重要原因;有氧运动则可通过抑制MMP-9与TIMP-1的表达失衡从而有效改善老年高血压心肌纤维化程度。

Objective： This study detected the effect of aerobic exercise on myocardial fibrosis in aged spontaneously hypertensive rats（ SHR） and explored the possible mechanism of the expression of matrix metalloproteinase. Methods： Twelve male SHRs were randomly assigned to a sedentary group（ SHR-SED） and an exercise training group（ SHR-EX）,and also 12 male WKYs were randomly assigned to a sedentary group（ WKY-SED） and an exercise training group（ WKY-EX）. SHR-EX and WKY-EX underwent treadmill training at 20 m / min for 60 min,5 d /wk,for 8 weeks. After 8 weeks,blood pressure,heart mass index,the expression of myocardial collagen fiber,and the protein expression of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 were examined.Results： 1） The systolic blood pressure（ SBP） in SHR-SED group were significantly higher than that in WKY-SED group. Also,the SBP in SHR-EX group and WKY-EX group was significantly lower than that in SHR-SED group and WKY-SED group respectively; 2） The heart mass index was significantly higher in SHR-SED group than that in WKY-SED group,and in SHR-EX group,it was significantly lower than that of SHR-SED group; 3） The CVF,expression of I,III collagen fibrils in SHR-SED group was significantly higher compared with WKY-SED group,and it was significantly lower in SHR-EX group compared with SHR-SED group; 4） Compared with WKY-SED group,MMP-9 and MMP-1 / TIMP-1 were significantly higher in SHR-SED group,and compared with SHE-SED group,it was significantly lower in SHR-EX group. Conclusion： Aging induces significant myocardial fibrosis in SHR,which may be related to the imbalance of MMP-9 and TIMP-1; aerobic exercise can inhibit this imbalance and markedly suppress the aging-induced myocardial fibrosis in SHR.