persistence or delayed occurrence of toxic effects. At the end of administered period, animals were fasted overnight, but with water ad libitum. They were then anesthetized with pentobarbital sodium 0.045 g/kg (i.p.) (Nembutals, Sigma-Aldrich, Shanghai, 5 g), and blood samples were obtained by retro-orbital puncture, using capillary tubes for hematological and biochemical studies, with and without anticoagulant ethylene diamine tetraacetic acid (EDTA), respectively. At the end of the recovery period the rem- aining rats are treated by the same method.