雄激素对糖皮质激素致大鼠不同类型骨骼肌萎缩的拮抗作用研究

目的:探讨地塞米松对不同类型骨骼肌的致萎缩作用以及睾酮的拮抗效果.方法:雌性SD大鼠160只,随机分为4组(n=40):①对照组:前肢皮下注射芝麻油1 ml·kg-1·d-1,连续3 d后同时腹腔注射生理盐水1 ml·kg-1·d-1,每日1次;②地塞米松组:注射地塞米松1 mg·kg-1·d-1(代替生理盐水)和芝麻...

The antagonistic effect of androgen on atrophy in different types of skeletal muscles in dexamethasone treated rats

Objective：To investigate the effect of androgen on atrophy of different types of skeletal muscles in dexamethasone-treated rats. Methods： One hundred and sixty female SD rats were randomly divided into four groups （n=40） as follows： the rats in the control group （CON group） received hypodermic injection of 1 ml · kg-1 · d-1 sesame oil in forelimb, and intraperitoneally injection of 1 ml · kg-1 · d-1 normal saline 3 days later; the rats in the dexamethasone group （DEX group） received injection of dexamethasone 1 mg· kg-1 · d 1 （instead of normal saline） and sesame oil; the rats in the testosterone group （TES group） received injections of testosterone 5 mg · kg-1 · d-1 （ instead of sesame oil） and normal saline; the rats in the testosterone ＋ dexamethasone group （TES ＋DEX group） received injections of same doses of dexamethasone and testosterone as in former groups. Animals were sacrificed 1, 3, 5 or 10 days after dexamethasone or saline injections. Muscles including extensor digitorum longus muscle （EDL）, soleus muscle （SL）, tibialis anterior muscle （TA） were harvested and weighed. Muscle fiber cross-sectional area （CSA） was determined by imaging processing system after musclc fiber cross-section after HE staining. Results：The weight of EDL, SL or TA in the CON group and TES group increased gradually, and the weight of the EDL and TA in the DEX group decreased gradually. On 10 days, the weight and muscle fiber CSA of the EDL and TA in the DEX group were lower significantly than those in the CON group （P〈 0.01）, and the weight and muscle fiber CSA in the TES＋DEX group were higher significantly than those in the DEX group （P〈0.01 or P〈0. 05）. The weight and muscle fiber CSA of the SL showed no significant difference among the DEX group, CON group and TES＋DEX group （P〈 0. 05）. Conclusion：Dexamethasone can induce skeletal muscular atropy in fast （white） muscles, but not in slow （red） muscles, and testosterone can partially prevent skeletal muscular atrophy induced by dexamethasone. The changes in muscle weight are associated with muscle fiber hypertrophy or atrophy.