The Role of Glutathione in Dichloromethane Toxicity to

Abstract Growth rate of Lemna paucicostata was significantlydecreased by dichloromethane treatment; exhibitingIC 25 , IC 50 , and IC 75 values of 4.73 g/L, 74.72 g/L, and124.18g/L, respectively. At the IC 25 concentration, anincrease in ascorbate content and a concomitantdecrease in lipid peroxidation level were exhibited,indicating an adaptive induction of ascorbate synthe-sis to protect membrane in response to oxidativestress caused by low level of dichloromethane. Atthe concentrations higher than IC 50 , dichloromethanecaused significant increases in reactive oxygen spec-ies formation and lipid peroxidation and caused simul-taneous decrease in glutathione (GSH) and ascorbatecontents, implying the treatment-induced oxidativedamage. Our results demonstrated that dichlorome-thane caused a decrease in glutathione reductase toglutathione peroxidase activity ratio, which disabledrecycling of GSH and led to a depletion of glutathionepool. This suggests that the decline of glutathioneredox cycling may play a crucial role in dichlorome-thane-induced oxidative damage and toxicity to