[Influence of heat shock protein 90 on protein serine threonine kinases expression in hypoxic cardiomyocytes].
OBJECTIVE
To explore the effect of endogenous heat shock protein 90 (HSP90) on the AKT signaling pathway of hypoxic cardiomyocytes.


METHODS
The hypoxia model of neonatal rat cardiomyocyte was established. The cells were randomly divided into normal control, hypoxia, Geldanamycin (GA, with hypoxia after Geldanamycin treatment) groups. The myocardial cell activity and the expression of endogenous HSP90 and AKT were determined with MTT and Western blotting, respectively at 1, 3, 6, 12, 24 and 48 post-hypoxia hours (PHH). The apoptotic index (AI) of cardiomyocytes were determined with TUNEL method at 24 PHH.


RESULTS
(1) At 24 and 48 PHH, the activity of cardiomyocytes in hypoxia group and GA group were evidently lower than that in control group (P < 0.05). The activity of cardiomyocyte in GA group began to decrease at 12 PHH, and it was obviously lower than that in hypoxia group at 48 PHH (P < 0.05). (2) At 24 PHH, the AI in hypoxia group (10.7 +/- 1.2)% was obviously higher than that in normal control group [(1.9 +/- 0.3)%, P < 0.05], while it was obviously lower than that in GA group [(26.3 +/- 5.3)%, P < 0.01]. (3) The expression of endogenous HSP90 and AKT in hypoxia and GA groups were markedly increased compared with that of normal controls at 12 PHH, and it decreased at 24 PHH in hypoxia and GA groups, especially in the latter.


CONCLUSIONS
Endogenous HSP90 plays important roles in maintaining the cardiomyocyte activity, and its level might affect the expression of AKT.
Zhao
Xiao-hui
XH
Institute of Burn Research, Southwest Hospital, State Key Laboratory of Trauma, Burns and Combined Injury, the Third Military Medical University, Chongqing, P. R. China.
Peng
Yi-zhi
YZ
Wang
Yuan-yuan
YY
Huang
Yue-sheng
YS
D000818:Animals; D015687:Cell Hypoxia; D002478:Cells, Cultured; D004195:Disease Models, Animal; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction
D018841:HSP90 Heat-Shock Proteins; D051057:Proto-Oncogene Proteins c-akt