Fig. 6. Isoflurane decreases SOX2 expression. With the use of matched plates, neural stem cells were exposed to control conditions or isoflurane, 0.7, 1.4, or 2.8%, for 6 h. Cells were fixed and stained 24 h later with SOX2 (Alexa Fluor 555; red ) and Hoechst 33342 (blue ). SOX2-stained cells in a control plate 24 h after treatment (A) . SOX2 staining in a matched plate 24 h after isoflurane, 2.8%. Hoechst (33342) nuclear staining (blue ); SOX2 staining (red ) (B) . There was no effect of isoflurane on the percentage of cells expressing SOX2 (C) , but isoflurane 1.4 (P = 0.024) (D) and 2.8% (P = 0.012) (E) produced a 7% and 14% decrease, respectively, in nuclear expression of SOX2. Data are expressed as mean ± SD for N = 8 wells per treatment condition (eight images per well using a 20× objective and appropriate filters) at each time point. **P ⩽ 0.01 by Student t test.