Taurine antagonized oxidative stress injury induced by homocysteine in rat vascular smooth muscle cells.
OBJECTIVE
To observe protective effects of taurine on reactive oxygen species generation induced by homocysteine in rat vascular smooth muscle cells (VSMC).


METHODS
Rat VSMC was incubated with various concentrations of homocysteine and taurine. The lactate dehydrogenase (LDH) activity which released into culture medium was elevated as an indicator for VSMC injury. The reactive oxygen species (ROS)--hydrogen peroxide (H2O2) and superoxide anion (O2(-*)) were measured with luminol or lucigenin chemiluminescence method, and the mitochondria Mn-superoxide dismutase (Mn-SOD) and catalase (CAT) were also measured in treated VSMC.


RESULTS
LDH leakage from cultured VSMC treated with homocysteine, was increased (P<0.01 vs control), and it was markedly inhibited when co-incubated with taurine (P<0.01). Homocysteine induced H2O2 generation from VSMC in a concentration dependent manner (P<0.01 vs control). However, taurine (5, 10, and 20 mmol/L) significantly antagonized 0.5 mmol/L homocysteine-induced H2O2 generation in VSMC in a concentration dependent manner (P<0.01 vs homocysteine alone group), although taurine itself did not alter the H2O2 generation in VSMC (P>0.05 vs control). In this study, the superoxide anion in VSMC was not detectable by chemiluminescence method. In addition, treatment of VSMC with taurine increased mitochondria Mn-SOD and CAT activity in a concentration dependent manner (P<0.05), but homocysteine decreased mitochondria Mn-SOD and CAT activity (P<0.01 vs control). In addition, co-administration of taurine markedly ameliorated homocysteine-induced inhibition of Mn-SOD and CAT activity in VSMC (P<0.01 vs homocysteine alone group).


CONCLUSIONS
Taurine antagonized the effects of homocysteine on ROS generation and anti-oxidant enzyme activities in rat VSMC in vitro.
Institute of Cardiovascular Diseases, the First Hospital, Peking University, Beijing 100034, China.
Lin
L
Chang
Jian-xin
JX
Xu
Jing
J
Zhao
Yong-zheng
YZ
Pang
Chao-shu
CS
Tang
Yong-fen
YF
Qi
D000818:Animals; D001011:Aorta / Q000166:cytology; D002374:Catalase / Q000378:metabolism; D006710:Homocysteine / Q000037:antagonists & inhibitors*; D006861:Hydrogen Peroxide / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D013654:Taurine / Q000494:pharmacology*
D017382:Reactive Oxygen Species; D006710:Homocysteine; D013654:Taurine; D006861:Hydrogen Peroxide; D007770:L-Lactate Dehydrogenase; D002374:Catalase; D013482:Superoxide Dismutase