目的 观察不同频率牵拉对兔跟腱组织学表现和Ⅰ型、Ⅲ型胶原蛋白表达的影响，探讨牵拉频率与腱病之间的关系。方法 45只雄性新西兰大白兔随机分成3组，其中一组作为对照组未施加电刺激，另两组施加电刺激腓肠肌以牵拉跟腱，电刺激频率分别为0.17和1 Hz。光镜下观察兔跟腱组织学变化，免疫组化检测Ⅰ型、Ⅲ型胶原蛋白的表达情况。结果 牵拉4周后，1 Hz组Ⅰ型胶原明显减少，Ⅲ型胶原表达明显增加，但胶原总量减少。牵拉6周后，1 Hz组跟腱组织呈现出腱病病理学特征；0.17 Hz组Ⅰ型胶原蛋白表达明显增加，而Ⅲ型胶原表达无明显变化。结论 高频率牵拉可造成跟腱腱病的发生，而低频率牵拉对受损跟腱可能具有修复作用。

Objective To investigate the effect of stretch in different frequencies on histologic appearance and expressions of typeⅠand type Ⅲ collagen protein in Achilles tendons of rabbits, so as to explore the relationship between stretch frequency and tendinopathy. Methods Fourty-five male New Zealand white rabbits were randomly divided into 3 groups, one was control group without electrical stimulus and the other two groups were electrically stimulated to drag Achilles tendon in the frequencies of 0.17 and 1 Hz, repetitively. The histologic appearance was observed under light microscopic, and expressions of typeⅠand type Ⅲ collagen protein were measured by immunohistochemistry staining. Results After 4 weeks of stretch, the expression of type Ⅰ collagen protein decreased, while the expression of type Ⅲ collagen protein increased, but total collagen protein expression decreased. After 6 weeks of stretch, Achilles tendon tissues presented typical tendinopathy in histology in 1 Hz group, and the expression of type Ⅰ collagen protein increased, while the expression of type Ⅲ collagen protein had no change in 0.17 Hz group. Conclusions High-frequency stretch results in tendinopathy in Achilles tendon, while low-frequency stretch may play a role in its repair.