Figure 2.

(A) Cell viability evaluated by a modified MTT assay was measured in GT1 cell lines after BSO challenge. Each of the infected lines, GT1^Chl, GT1^22L, and GT1^FK, presented an increased sensitivity to 1,000 μM BSO when compared with control GT1–7, GT1^87V, and GT1^Mock. CR-treated cells, GT1^Chl-CR, recovered a normal phenotype when compared with infected GT1^Chl cells. [Bars represent means ± SD; and *, P < 0.01 (Student's t test)]. (B) The phase contrast microscopy of BSO-challenged GT1 lines showed an intense cell death in the infected cell lines GT1^Chl and GT1^22L when compared with control GT1–7. (C) Total glutathione levels (GSH) were similar in all cell lines and decreased alike on treatment with various concentrations of BSO. (D) N-acetylcysteine preincubation (1 h; 1 mM) showed a significant protective effect on cell viability in the presence of 1 mM BSO. [Bars represent means ± SD; and *, P < 0.01 (Student's t test)].