家兔小腿屈伸趾肌群肌纤维型增龄变化研究

Research on Muscle Fiber Type of Flexor and Extensor Digitorum Muscles in Rabbit's Legs with Aging

目的使用NADH-TR染色探讨家兔屈伸趾肌群在增龄过程中肌纤维型的改变。方法健康家兔24只,根据家兔年龄段划分为:幼年组(4周)、青年组(12月)、中年组(24月)、老年组(36月)共4个组。取肌腹中部横切片作烟酰胺腺嘌呤二核苷酸四唑氧化还原酶(NADH-TR)染色。结果 4周组能分辨出Ⅰ、ⅡA和ⅡB三型肌纤维;36月龄组的Ⅱ型肌纤维尤其是ⅡB型肌纤维构成比减少,Ⅰ型肌纤维呈增加趋势,出现小角化肌纤维和肌纤维类聚现象。结论随着增龄家兔骨骼肌三型肌纤维的分布逐渐改变,骨骼肌萎缩以Ⅱ型肌纤维为主。

Objective This study aimed to explore the change of muscle fiber type of flexor and extensor digitorum muscles in rabbit＇s legs with aging by NADH-TR staining. Methods A total of 24 healthy rabbits were divided into 4 groups respectively： Infant group（4 weeks）,Youth group （12 months）, Middle-aged group（24 months ） and Elderly group（36 months）. The transverse section of muscle belly was stained by NADH-TR. Results The type Ⅰ , type Ⅱ A and type Ⅱ B muscle fibers were distinguished in the 4 weeks group. In the 36 month group, the composition ratio of type Ⅱ,especially the type Ⅱ B, decreased, while type Ⅰpresented a rising tendency, a small angular shape and clustering of muscle fiber types could be observed. Conclusion The distribution of the rabbit three skeletal muscle fiber types gradually transformed with aging , and the type Ⅱ muscle fibers gradually atrophy with aging.