[Influence of mechanical stretch on the expression of myosin heavy chain mRNA in cardiomyocyte subjected to ischemia and hypoxia].
OBJECTIVE
To investigate the influence of mechanical stretch on the expression of myosin heavy chain (MHC) mRNA in cardiomyocyte subjected to ischemia and hypoxia.


METHODS
Mechanical stretch model of in vitro cultured cardiomyocyte was established for the study. The cells were processed by non-sugar hypoxic stimuli to simulate postburn ischemic and/or hypoxic injuries. The cells were then divided into normal control (N), 10% stretch (S), ischemic and hypoxic culture (IHC), 10% stretch with ischemia and hypoxia (SIHC) groups. The changes in MHC mRNA expression were observed at 1, 3, 6 and 12 post treatment hours (PTHs) by RT-PCR and were statistically analyzed with gel image analysis software.


RESULTS
The expression of both alpha and beta MHC mRNA increased in 10% stretch group, especially of beta MHC mRNA (P < 0.01). The transformation of alpha MHC mRNA to beta MHC mRNA was accelerated in IHC group, and alpha MHC mRNA expression was decreased at 12 PTH. The expression of beta MHC mRNA was increased after ischemia and hypoxia, peaked at 6 PTH, and decreased thereafter (P < 0.05). The transformation of alpha MHC mRNA to beta MHC mRNA was more obvious in SIHC group, and which was intensified along with the elapse of stimulation time. The expression of both alpha and beta MHC mRNA were down-regulated at 12 PTH (P < 0.05).


CONCLUSIONS
Down regulation of MHC mRNA expression by ischemia and hypoxia could be aggravated by mechanical stretch, indicating that mechanical stretch might be a possible cause for cardiac dysfunction.
Institute of Burn Research, Southwest Hospital, State Key Laboratory of Trauma, Burns and Combined Injury, Third Military Medical University, Chongqing 400038, China.
Xiao-Dong
XD
Li
Yue-Sheng
YS
Huang
Jia-Ping
JP
Zhang
D000818:Animals; D015687:Cell Hypoxia; D002478:Cells, Cultured; D017202:Myocardial Ischemia / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley
D012333:RNA, Messenger; D018995:Myosin Heavy Chains