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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 effects of aerobic training and intensive fatigue training on the expression of type Ⅰ and Ⅲ collagen fibers and matrix metalloproteinase-13 (MMP-13) in atrioventricular node (AVN) of rats. Methods: Thirty-six male Sprague-Dawley rats aged 3 months were randomly divided into three groups: the control group, the aerobic training group and the fatigue training group. The model of aerobic training and fatigue training was established by treadmill training. The type Ⅰ and type Ⅲ collagen fibers in AVN were observed by picric acid-sirius red staining and transmission electron microscopy. The expression of MMP-13 in AVN was observed by immunohistochemical SABC The change. Results: Compared with the quiet control group, the AVN organization in the aerobic training group was normal, the distribution of type Ⅰ and type Ⅲ collagen fibers was uniform and significantly increased (P <0.05), and the ratio of typeⅠ / Ⅲ collagen fibers had no significant change; the expression of MMP-13 was significant Higher than the quiet control group (P <0.05). Compared with the quiet control group and the aerobic training group, the type Ⅰ collagen fibers in the AVN area of the fatigue training group showed hyperplasia, area reduction and distortion, and the type I collagen fibers were significantly increased (P <0.05). The ultrastructure of the type Ⅲ collagen fiber was broken (P <0.05). The ratio of type Ⅰ / Ⅲ collagen fibers increased. The expression of MMP-13 was significantly higher than that of the quiet control group and aerobic training group (P <0.05). CONCLUSION: Different intensity exercise training can change the morphology and the expression of MMP-13 of type Ⅰ and type Ⅲ collagen fibers in AVN of rats. Aerobic training can protect normal AVN type Ⅰ and type Ⅲ collagen fibers and fatigue Training can cause the pathological changes of type Ⅰ and type Ⅲ collagen fibers in AVN. It is speculated that this may be related to the increased expression of MMP-13 induced by fatigue training.