Abstract:

Objective　To evaluate the effect of stretch on sarco(endo)plasmic reticulum Ca2+-Mg2+ATPases activity and mR- NA level and study the remodeling reaction of muscle in a variety of mechanical environments.Methods　Myoblast from maxillo- facial skeletal muscle of one-week-old male Sprague-Dawley ratwas cultured and stretched cyclicly using a four-point bend device. Inorganic Phosphorus test was used to compare the activity of Ca2+-Mg2+ATPases of myoblast before and after stretch. RT-PCR was also used to observe the Ca2+-Mg2+ATPases mRNA level.Results　The activity of Ca2+-Mg2+ATPases of myoblast down regulated significantly in 4 hours. During the period of 8 hours to 24 hours, up-regulation followed then returned to control level at the 48 hour point. RT-PCR showed that Ca2+-Mg2+ATPases mRNA level were elevated by stretch, particularly at 2 hour and 48 hour point.Conclusion　The results suggested a transcriptional control of Ca2+-Mg2+ATPases activitywas involved in the muscle remodeling process induced by stretch.

Key words: stretch, myoblast, Ca2+-Mg2+ATPases