Intracellular GSH level is a factor in As4.1 juxtaglomerular cell death by arsenic trioxide

Arsenic trioxide has been known to regulate many biological functions such as cell proliferation, apoptosis, differentiation, and angiogenesis in various cell lines. We investigated the involvement of GSH and ROS such as H ₂O₂ and O₂^.- in the death of As4.1 cells by arsenic trioxide. The intracellular ROS levels were changed depending on the concentration and length of incubation with arsenic trioxide. The intracellular O₂^.- level was significantly increased at all the concentrations tested. Arsenic trioxide reduced the intracellular GSH content. Treatment of Tiron, ROS scavenger decreased the levels of ROS in 10 μM arsenic trioxide-treated cells. Another ROS scavenger, Tempol did not decrease ROS levels in arsenic trioxide-treated cells, but slightly recovered the depleted GSH content and reduced the level of apoptosis in these cells. Exogenous SOD and catalase did not reduce the level of ROS, but did decrease the level of O₂^.-. Both of them inhibited GSH depletion and apoptosis in arsenic trioxide-treated cells. In addition, ROS scavengers, SOD and catalase did not alter the accumulation of cells in the S phase induced by arsenic trioxide. Furthermore, JNK inhibitor rescued some cells from arsenic trioxide-induced apoptosis, and this inhibitor decreased the levels of O ₂^.- and reduced the GSH depletion in these cells. In summary, we have demonstrated that arsenic trioxide potently generates ROS, especially O₂^.-, in As4.1 juxtaglomerular cells, and Tempol, SOD, catalase, and JNK inhibitor partially rescued cells from arsenic trioxide-induced apoptosis through the up-regulation of intracellular GSH levels.