运动训练对大鼠房室结Ⅰ、Ⅲ型胶原纤维组织结构及MMP-13表达的影响

Effects of Aerobic Exercise on the Collagen Fibers and the Expression of MMP-13 in Atrioventricular Node of Rats

目的:探讨有氧训练和大强度疲劳训练对大鼠房室结(AVN)Ⅰ、Ⅲ型胶原纤维及基质金属蛋白酶13(MMP-13)表达的影响。方法:3月龄雄性Sprague-Dawley大鼠36只,随机分为安静对照组、有氧训练组和疲劳训练组3组。采用跑台训练方式分别建立大鼠有氧训练和疲劳训练模型,采用苦味酸-天狼猩红染色和透射电镜观察AVN区Ⅰ、Ⅲ型胶原纤维,免疫组织化学SABC法观察AVN区MMP-13表达的变化。结果:与安静对照组比较,有氧训练组AVN组织结构正常,Ⅰ、Ⅲ型胶原纤维分布均匀且显著增多(P<0.05),Ⅰ/Ⅲ型胶原纤维比值无明显变化;MMP-13表达显著高于安静对照组(P<0.05)。与安静对照组和有氧训练组比较,疲劳训练组AVN区Ⅰ型胶原纤维增生异常,区域减少和扭曲,且I型胶原纤维显著增多(P<0.05),Ⅲ型胶原纤维超微结构出现断裂,且Ⅲ型胶原纤维显著减少(P<0.05),Ⅰ/Ⅲ型胶原纤维比值升高;MMP-13表达均显著高于安静对照组和有氧训练组(P<0.05)。结论:不同强度运动训练可使大鼠AVN区Ⅰ、Ⅲ型胶原纤维的形态结构和MMP-13的表达发生不同程度的变化,有氧训练可保护大鼠AVNⅠ、Ⅲ型胶原纤维结构正常,疲劳训练可造成AVN区Ⅰ、Ⅲ型胶原纤维发生病理改变,推测可能与疲劳训练诱导MMP-13表达增加有关。

Objective To investigate the effect of aerobic exercise and exercise-induced fatigue on the type I ,Ⅲ of collagen fibers and matrix metalloproteinase-13 （MMP-13） in atrioventricular node （AVN） of rats. Methods Thirty six 3-month old male Sprague-Dawley rats were randomly divided into three groups： control group（C）, aerobic training group （AT） and exercise induced-fatigue group （EIF）. Rat models of aerobic exercise and exercise-induced fatigue were established through running on an animal treadmill. Picric-sirius red staining and transmission electron microscope were applied to display the fibers of type I ,Ⅲ, and immunohistochemical SABC method was applied to observed the expression of MMP-13 in AVN. Results As compared with that in group C, the microstructure of AVN was normal, and the collagen type I , Ⅲ fibers in AVN increased significantly and were well-distributed in group AT （P 〈0.05）, and the ratio of I/Ⅲ remained unchanged. The expression of MMP-13 in group AT was significantly higher than that in group C （P 〈0.05）. As compared with that in group C and group AT, the type I fiber proliferated abnormally in AVN, distortion and vacuole revealed in part; the number of type I increased significantly （P 〈0.05）; fragmentation of type Ⅲ appeared and number of type Ⅲ fibers reduced significantly（P 〈0.05）; the ratio of I/Ⅲ and the expression of MMP-13 increased significantly in group EIF （P〈0.05）. Conclusions Aerobic training could protect the normal structure of type I and Ⅲ collagen fibers in AVN, and exercise-induced fatigue could increase the expression of MMP-13 in AVN and probably cause pathological changes in AVN.