Production of reactive oxygen species by toxin T-514 of genus Karwinskia in vitro.
In the present study we have analyzed the production of reactive oxygen species by toxin T-514 of the genus Karwinskia in vitro (primary liver cell cultures and microsomes), as well as their possible role in its cytotoxicity. The role of catalase and superoxide dismutase (SOD) as defense mechanisms against oxidative stress was also studied. Freshly isolated hepatocytes or microsomes were exposed to T-514 in the presence or absence of catalase and SOD. Cytotoxicity was determined by methylthiazoltetrazolium (MTT) reduction. Oxidative stress was evaluated by the dichlorofluorescein diacetate (DCFDA) fluorescent probe and the reduction of ferricytochrome c. Exposure of hepatocytes to toxin T-514 for 2-, 4-, 6- and 24-h periods resulted in a time- and concentration-dependent increase in the suppression of mitochondrial metabolic activity. T-514 induced the production of reactive oxygen species in both hepatocytes and microsomes. Catalase and superoxide dismutase had a protective effect against the cytotoxicity of T-514 in hepatocytes and also inhibited the production of oxygen reactive species in microsomes. The results indicate that oxidative stress mediated by reactive intermediates may be a mechanism by which T-514 induces its cytotoxic effect.
Garza-Ocañas
L
L
Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Apdo. Postal 146, Col. del Valle, Nuevo León, Mexico. logarza@ccr.dsi.uanl.mx
Zanatta-Calderón
M T
MT
Acosta
D
D
Torres-Alanís
O
O
Piñeyro-López
A
A
D000818:Animals; D000873:Anthracenes / Q000009:adverse effects*; D002374:Catalase / Q000494:pharmacology; D003603:Cytotoxins; D022781:Hepatocytes; D031956:Karwinskia / Q000737:chemistry*; D008099:Liver / Q000166:cytology; D008297:Male; D008862:Microsomes, Liver; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase / Q000494:pharmacology
D000873:Anthracenes; D003603:Cytotoxins; D017382:Reactive Oxygen Species; C075149:Karwinskia toxin T-514; D002374:Catalase; D013482:Superoxide Dismutase