Endogenous nitric oxide mediates lipoteichoic acid induced preconditioning on reoxygenation injury of cultured human coronary artery endothelial cells.
OBJECTIVE
To explore the effects of lipoteichoic acid (LTA) induced delayed preconditioning (PC) on hypoxia-reoxygenation (H/R) injury of cultured human coronary artery endothelial cells (HCAECs), and to investigate the potential role of endogenous nitric oxide (NO) participated in the protective mechanism.


METHODS
HCAECs were incubated for 2 h in a hypoxic atmosphere and reoxygenated for 4 h in a normoxic atmosphere. The delayed PC was induced by pretreatment with LTA (30 or 300 microg x L(-1)) for 4 h before 24 h recovery. The extent of cellular injury after reoxygenation was assessed by the percentage of cellular injury with Trypan blue exclusion and by the amount of lactate dehydrogenase (LDH) in culture media. The NO level of the culture media was measured spectrophotometrically. Furthermore, HCAECs were exposed to 300 microg x L(-1) of LTA for 4 h, and to detect the expression of eNOS mRNA by RT-PCR method after cells were recovered from different points.


RESULTS
LTA pretreatment significantly decreased the percentage of the killed cell and the concentration of LDH in media. Also, LTA pretreatment obviously raised the concentrations of NO in culture media. The protective effects of LTA were abrogated by pretreatment with N-monomethyl-L-arginine (L-NMMA). Moreover, the expression of eNOS mRNA was significantly upregulated after HCAECs exposure to LTA for 4 h following 2 h or 4 h recovery.


CONCLUSIONS
LTA could induce the delayed protection against H/R induced endothelial injury and dysfunction of cultured HCAECs. NO produced by eNOS acts initially as a trigger and subsequently as a mediator of delayed PC.
Ma
Shi-yu
SY
Department of Cardiology of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China. syma@tjh.tjmu.edu.cn
Xiang
Ji-zhou
JZ
Wu
Ji-liang
JL
Ma
Ye-xin
YX
Hu
Ben-rong
BR
D000328:Adult; D016923:Cell Death; D015687:Cell Hypoxia; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000166:cytology / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008070:Lipopolysaccharides / Q000302:isolation & purification / Q000494:pharmacology*; D015428:Myocardial Reperfusion Injury / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013211:Staphylococcus aureus / Q000737:chemistry; D013682:Teichoic Acids / Q000302:isolation & purification / Q000494:pharmacology*
D008070:Lipopolysaccharides; D012333:RNA, Messenger; D013682:Teichoic Acids; D009569:Nitric Oxide; C009900:lipoteichoic acid; D007770:L-Lactate Dehydrogenase; D052250:Nitric Oxide Synthase Type III