Protection of vitamin C on the cardiac injury induced by nano-titanium dioxide in mice / 中国药理学与毒理学杂志

OBJECTIVE To observe the protection of vitamin C on the cardiac injury induced by 50 nm titanium dioxide inmice.METHODS Kunming mice were ad mistered by ig of vitamin C 100,200 and 400 mg·kg -1 for 2 d.And then the mice were ad mistered by ig of nano-TiO2 2 g·kg -1 and vitamin C (100.0,200.0 and 400.0 mg·kg -1 )for 3 d,the interval of treatment with nano-TiO2 and vitamin C was 4 h.The mice were scarified 24 h later after the last ad ministration.Electrocardiogra m (ECG)was determinated by physiological recorder.The myocardial enzy mes activities in serum and superoxide dismutase (SOD)and glutathione peroxidase(GSH-Px)activities in serum and myocardial tissue were determinated by bioche mical method.Cometassay was used to detect the DNA da mage of the heart. Heart tissue was used for histopathological exa mination by HE staining.RESULTS Co mpared with the control,ECG showed higher S-T and T-wave a mplitude of nano-TiO2 2 g·kg -1 (P<0.05).The myocar-dial enzy mes activities significantly increased and activities of SOD and GSH-Px significantly decreased in nano-TiO2 group,compared with the control group(P <0.05).Cometassay showed that olive tail mo ment (OTM)was significantly increased after nano-TiO2 2 g·kg -1 ,compared with the control group (P<0.05).The histopathology showed ede ma of myocardial cells,myofibril disorders and increasing infla mmatory cells.Vita min C 100,200 and 400 mg·kg -1 can decrease S-T in ECG,OTM,myocardial enzy mes activities,increase the SOD and GSH-Px activities in serum and myocardial tissue;reduce myocardial hypertrophy and infla mmatory cells.CONCLUSION nano-TiO2 can induce myocardial injury inmice and vitamin C can alleviate the da mage.The mechanism may be associated with the antioxidant ability of vitamin C inmyocardial tissue.

Lipoxygenase-mediated oxidative metabolism and oxidative stress / 中国药理学与毒理学杂志

There is a close relationship between oxidative stress induced tissue damage and many diseases.As a multi-function oxidase,lipoxygenase can generate reactive oxygen species (ROS)by oxidatively metabolizing various endogenous and exogenous chemicals such as drugs and environmental pollutants.Lipoxygense can catalyze endogenous che mical reaction,such as arachidonic acid and pro-duce ROS.Lipoxygenase can be also activated in other ways to generate ROS by activating signal trans-duction.Moreover,some exogenous chemicals can be metabolized into highly reactive radical intermedi-ates by lipoxygenase,inducing ROS generation.The accumulation of intracellar ROS can damage intra-cellar redox balance and induce oxidative stress.That may be one of the possible toxic effect mecha-nis ms of che mical agents.