慢性心衰大鼠心肌Klotho、ColⅠ和ColⅢmRNA的表达及其相关性

Expression of Klotho, Col Ⅰ and Col Ⅲ mRNAs in myocardium of rats with chronic heart failure and their correlation

目的探讨慢性心衰大鼠心肌中Klotho基因、Ⅰ型胶原(ColⅠ)m RNA和Ⅲ型胶原(ColⅢ)m RNA的表达及其相关性。方法清洁级SD大鼠20只,体重250~300 g,随机分为心衰模型组和正常对照组,每组10只,心衰模型组连续14 d腹腔注射异丙肾上腺素3 mg/(kg·d)建立心衰大鼠模型,正常对照组不做处理。建模2 w后,全部大鼠称体重后处死,取心脏称重,并计算心脏湿重/体重指数(HW/BW);RT-PCR检测各组大鼠心肌组织中Klotho基因以及ColⅠ和ColⅢm RNA的表达量,分析各指标间的相关性。结果成功建立大鼠心衰模型(LVEF<50%)。RT-PCR检测结果显示,心衰模型组大鼠心肌中Klotho m RNA的表达较正常对照组显著降低(P<0.05),而ColⅠ和ColⅢm RNA的表达量较正常对照组显著增加(P<0.05)。相关分析显示,大鼠心肌组织中Klotho m RNA表达量与心肌组织ColⅠ m RNA和ColⅢm RNA的表达量呈独立、显著的负相关(P<0.05)。结论心衰大鼠心肌中Klotho基因与ColⅠ及ColⅢm RNA的表达呈显著负相关,可能是Klotho基因抑制心肌纤维化的机制。

Objective To explore the expression of Klotho gene, Col I mRNA and Col Ⅲ mRNA in the myocardium of rats with chronic heart failure （CHF） and their correlation. Methods 20 clean sprague-dawley （SD） rats weighing 250-300 g were selected and randomly divided in to a heart failure model group and a normal control group, with 10 rats in each group; the heart failure model group was continuously treated with 3 mg/（kg·d） isoprenaline via intraperitoneal injection for 14 d to build a rat model of heart failure, and the normal control group was not treated. Two weeks after the modeling, all rats were weighed and sacrificed, and their hearts were taken out and weighed to calculate the heat weight/body weight （HW/BW） index; the real-time polymerase chain reaction （RT-PCR） technique was conducted to measure the expression levels of Klotho gene, Col I mRNA and Col Ⅲ mRNA in the myocardial tissue of rats, and then the correlation was analyzed. Resulte The rat model of heart failure was successfully established （LVEF〈50%）; The RT-PCR detection suggested that the expression level of Klotho mRNA in myocardium of rats in the heat failure model group was significantly lower than that in the normal control group （P 〈 0.05）, while the expression levels of Col I mRNA and Col Ⅲ mRNA in the heart failure model group was significantly higher than those in the normal control group （P 〈 0.05）. The correlation analysis showed independent and significantly inverse correlation between the expression level of Klotho mRNA and the expression levels of Col I mRNA and Col Ⅲ mRNA in the myocardial tissue of rats （P 〈 0,05）. Conclusion The expression of Klotho gene is significantly inversely correlated with the expression of Col I mRNA and ColⅢ mRNA in the myocardium of rats with CHF; this may be resulted from the inhibition of Klotho gene on myocardial fibrosis.