[Changes of sarco(endo)plasmic reticulum Ca2+-Mg2+-ATPase activity of cultured myoblast induced by cyclic stretch].
OBJECTIVE
To evaluate the effect of stretch on sarco(endo)plasmic reticulum Ca2+-Mg2+ ATPases activity and mRNA level and study the remodeling reaction of muscle in a variety of mechanical environments.


METHODS
Myoblast from maxillofacial skeletal muscle of one-week-old male Sprague-Dawley rat was 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.


CONCLUSIONS
The results suggested a transcriptional control of Ca2+-Mg2+ ATPases activity was involved in the muscle remodeling process induced by stretch.
Che
Xiao-xia
XX
Dept. of Orthodontics, Beijing Stomatology Hospital, Beijing 100050, China.
Zeng
Hong
H
Luo
Song-jiao
SJ
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism*; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D008297:Male; D032446:Myoblasts / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*
D017301:Ca(2+) Mg(2+)-ATPase