不同恢复方式对废用性骨骼肌纤维类型的影响

Objective To observe the effects of eccentric exercise in counteracting the gastroenemius atrophy and muscle fibre types transformation induced by simulated weightlessness. Method Thirty female Sprague-Dawley rats were randomly assigned to three groups: control(CON), two-week tail-suspension 1 and 2(TS1, n=6＆TS2, n=12). After two weeks, the control and TS1’s gastroenemius were dissected and weighed. The TS2 were continued to randomly assign to two groups: normal rehabilitation group(NR,n=6), eccentric exercise rehabilitation group(ER,n=6). After two weeks’ rehabilitation , gastroenemius was sectioned with cryostat and stained with ATPase staining. The cross sectional area (CSA) and the proportion of typeⅠ, IIa and IIb fibers were measured using Leica image analysis system..Result In TS, wet weights of the gastroenemius, CSA of typeⅠand IIb fibers, and proportion of typeⅠand IIa fibers decreased obviously, as compared with those rats in CON (P<0.01). Whereas in type IIb, the proportion were increased significantly compared with those rats in CON（p<0.01）.Under 14 days rehabilitation with different condition, eccentric exercise traning promoted the CSA and proportion of typeⅠ, IIa and IIb fibers recovering to normal levels（p>0.05）,whereas normal rehabilitation only restored the proportion of type I to normal levels but not the CSA.Conclusion eccentric exercise training fully promoted the the CSA and relative proportion of typeⅠ, IIa and IIb fibers in gastroenemius recovering from atrophy induced by simulated weightlessness for 14 daysin rats.