Isoniazid is one of the most commonly used drugs to treat tuberculosis. Its administration is associated with a high incidence of hepatotoxicity. The aim of this study was to establish the protective effects of taurine against cytotoxicity induced by isoniazid and its suspected toxic metabolite hydrazine in isolated rat hepatocytes by measuring reactive oxygen species (ROS) formation, lipid peroxidation, mitochondrial depolarisation, reduced glutathione (GSH), and oxidised glutathione (GSSG). Isoniazid caused no significant ROS formation in normal hepatocytes, but in glutathione-depleted cells it was considerable. Hydrazine caused ROS formation and lipid peroxidation in both intact and glutathione-depleted cells. Both isoniazid and hydrazine caused mitochondrial membrane depolarisation. Hydrazine lowered cellular GSH reserve and increased GSSG. Taurine (200 μmol L-1) and N-acetylcysteine (200 μmol L-1) effectively countered the toxic effects of isoniazid and/or hydrazine by decreasing ROS formation, lipid peroxidation, and mitochondrial damage. Taurine prevented depletion of GSH and lowered GSSG levels in hydrazine-treated cells. This study suggests that the protective effects of taurine against isoniazid and its intermediary metabolite hydrazine cytotoxicity in rat hepatocytes could be attributed to antioxidative action.
Reza Heidari, Hossein Babaei and Mohammad Ali Eghbal
Abbas Hosseinzadeh, Nouraddin Shayesteh, Hamid Zolfagharieh, Mohammad Babaei, Hasan Zareshahi, Hossein Mostafavi and Hadi Fatollahi
Gamma Radiation Sensitivity of Different Stages of Saw-Toothed Grain Beetle Oryzaephilus Surinamensis L. (Coleoptera: Silvanidae)
The effect of gamma irradiation on different developmental stages of Oryzaephilus surinamensis L., was investigated. Results showed that a required dose to prevent larval emergence from irradiated 1-2-days-old eggs was 60 Gray (Gy), and 350 Gy was required to prevent adult emergence from 15-days-old larvae. Also the required dose of radiation to prevent adult emergence from irradiated 5-days-old pupa was 700 Gy. The dose of 200 Gy caused 100% mortality of irradiated adults 28 days after treatment. In addition, the effect of gamma rays was studied on the developmental stage period of each irradiated stage till adult emergence. The results revealed that there was a dose-dependent increase of the developmental periods. The growth index of adults was significantly decreased with increasing dose of radiation administered to eggs, larvae and pupae. It is recommended that doses between 600 and 700 Gy should be used to control population growth of O. surinamensis when targeting pupae and adults present in stored products.