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[Changes of dystrophin and desmin in rat gastrocnemius under micro-damage induced by hypoxia.] [Ariticle in Chinese]

XU Yu-Ming, LI Jun-Ping, WANG Rui-Yuan

杭州师范大学体育与健康学院，杭州 310036； 北京体育大学研究生院，北京 100084

Abstract

To explore the changes and regulation mechanism of dystropin and desmin under muscle injury without mechanic stress, 40male Sprague-Dawley rats were randomly divided into 5 groups, which included normoxia control and hypoxia groups for 1, 2, 4 and7 d with 10% O2. Two rats from each group were examined for sarcolemma integrity using Evans blue dye (EBD) and EBD-positivefiber typing by metachromatic dye-ATPase method. The rest six rats from each group were analyzed for the changes of protein contentand gene expression using Western blot, RT-PCR and fluorescence assays. The results showed that the EBD-positive muscle fibers,mainly type IIA and type IIB, appeared at 1 d after hypoxia exposure. Both the ratio of EBD-positive cell and the mean fluorescencedensity were significantly higher in hypoxia groups than those in control group (P<0.05). The contents of dystrophin and desminfluctuated after hypoxia exposure, increased at 1 d, decreased at 2 d, increased dramatically again at 4 d, and returned to a normal levelat 7 d. Consistently, the gene expression began to increase significantly after 2 d. The total activity of calpain was significantly higherin hypoxia groups at 1, 4 and 7 d. Significantly higher levels of HSP70 and HSP90 were also observed at 4 and 7 d, respectively (P<0.05).These results suggest that the mechanical stress is not the only cause of damage of sarcolemma membrane integrity. In contrast toeccentric contraction, hypoxia-induced muscle damage is not accompanied by the loss of dystrophin and desmin. The types of musclefibers recruited by motor units and the activities of calpain may be important in hypoxia-induced damage of sarcolemma membraneintegrity.

Key words: Hypoxia; rat; gastrocnemius; sarcolemmal integrity; dystrophin; desmin; muscle damage

Received: 2010-03-15　　Accepted: 2010-05-17

Corresponding author: 王瑞元　　E-mail: wangry@vip.sina.com

Citing This Article：

XU Yu-Ming, LI Jun-Ping, WANG Rui-Yuan. [Changes of dystrophin and desmin in rat gastrocnemius under micro-damage induced by hypoxia.] [Ariticle in Chinese] . Acta Physiol Sin 2010; 62 (4): 339-348 (in Chinese with English abstract).