Melatonin reduces peroxynitrite-induced injury in aortic smooth muscle cells.
OBJECTIVE
To study the protective role of melatonin (MT) in peroxynitrite-induced injury in cultured aortic smooth muscular cells (ASMC).


METHODS
Peroxynitrite was synthesized chemically with a quenched flow reaction. Cells were exposed to peroxynitrite 500 micromol/L for 1 h in the absence or presence of various concentrations of MT 100, 300, and 500 micromol/L. Nitrotyrosine (NT), a specific "footprint"of peroxynitrite formation, was detected by immunohistochemical technique. The DNA damage was assayed by TUNEL technique. The levels of MDA in the medium and cell viability were measured.


RESULTS
Incubation of ASMC with peroxynitrite 500 micromol/L for 1 h elicited the increase in the extent of immunostaining for NT, the rate of the TUNEL-positive cell, the content of MDA in the medium, and the number of dead cell. Pretreatment of ASMC with MT 100-500 micromol/L decreased these peroxynitrite-induced changes in a concentration-dependent manner.


CONCLUSIONS
MT attenuated the injury induced by peroxynitrite in ASMC.
Zhou
Jun-lin
JL
Department of Hand Surgery, Third Affiliated Hospital, Hebei Medical University, Shijiazhuang 050051, China. zhjunlin@yahoo.com
Zhu
Xiao-guang
XG
Ling
Yi-ling
YL
Li
Qing
Q
D000818:Animals; D001011:Aorta / Q000166:cytology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004249:DNA Damage / Q000187:drug effects*; D016166:Free Radical Scavengers / Q000494:pharmacology; D008315:Malondialdehyde / Q000378:metabolism; D008550:Melatonin / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D030421:Peroxynitrous Acid / Q000037:antagonists & inhibitors*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism*
D016166:Free Radical Scavengers; D030421:Peroxynitrous Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; D008315:Malondialdehyde; D008550:Melatonin