Sarcolemmal sodium-calcium exchanger mediated the beneficial effects of myocardial ischemic preconditioning and pharmacological preconditioning.
- Author:
Bao-hua ZHU
1
;
Qun-ying XI
;
Chen LIU
;
Neng-feng ZHANG
Author Information
- Publication Type:Journal Article
- MeSH: Animals; Calcium; metabolism; Calcium-Calmodulin-Dependent Protein Kinase Type 2; antagonists & inhibitors; Cells, Cultured; Ischemic Preconditioning, Myocardial; L-Lactate Dehydrogenase; metabolism; Myocardial Reperfusion Injury; metabolism; therapy; Myocytes, Cardiac; metabolism; RNA, Messenger; metabolism; Rats; Rats, Sprague-Dawley; Sodium-Calcium Exchanger; metabolism
- From: Chinese Journal of Cardiology 2006;34(4):367-371
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVETo investigate the role of sodium-calcium exchanger (NCX) on ischemic preconditioning and pharmacological preconditioning.
METHODSCultured rat neonatal cardiomyocytes were randomly divided into 6 groups: (1) ischemia/reperfusion group (9 h ischemia followed by 1 h reperfusion, I/R), (2) ischemic preconditioning group (1.5 h ischemia/1 h reperfusion + I/R), (3) pharmacologic preconditioning group, adenosine (10 micromol/L) pretreated for 1 h + I/R, (4) calmodulin-dependent protein kinase II (CaMKII) inhibitor KN-93 (0.5 micromol/L for 0.5 h) + ischemic preconditioning group, (5) KN-93 + pharmacologic preconditioning group, (6) control group. The leakage of intracellular lactate dehydrogenase (LDH) in various groups was determined by biochemical autoanalyzer. Semi-quantitative RT-PCR was employed to measure the mRNA levels of sodium-calcium exchanger. Activity of sodium-calcium exchanger (Na(+)-dependent (45)Ca(2+) uptake) was measured by liquid scintillation counting.
RESULTS(1) Compared to the I/R group, the LDH leakages in both ischemic preconditioning group and pharmacologic preconditioning group were significantly reduced (P < 0.05) while significantly increased in the KN-93 + pharmacologic preconditioning group and the KN-93 + ischemic preconditioning group (P < 0.05). (2) The Na(+)-dependent (45)Ca(2+) uptake was significantly increased in the I/R group (P < 0.05) compared to control group and this increase could be significantly attenuated in ischemic preconditioning group and adenosine pretreatment group (P < 0.05). (3) The expression of NCX mRNA in I/R group was also significantly increased (P < 0.05) in the I/R group (P < 0.05) compared to control group and this increase could be significantly attenuated in ischemic preconditioning group and adenosine pretreatment group (P < 0.05), CaMKII inhibitor KN-93 significantly abolished these effects in preconditioning group (P < 0.05) and in adenosine pretreated group (P < 0.05).
CONCLUSIONNCX mediated the cardioprotective effects of ischemic preconditioning and pharmacological preconditioning in the neonatal cardiomyocytes I/R model.
