Fig. 1. Treatment of nitrous oxide plus isoflurane induces caspase-3 activation and apoptosis, and increases levels of BACE and Aβ in H4-APP cells. (  A ) Effects of 70% nitrous oxide plus 1% isoflurane for 6 h and staurosporine on caspase-3 activation. Each band in the Western blot represents an independent experiment. There is no significant difference in amounts of β-actin in the control condition-, staurosporine-, or nitrous oxide plus isoflurane–treated H4-APP cells. (  B ) Caspase-3 activation assessed by quantifying the ratio of caspase-3 fragment to FL caspase-3 in the Western blots, normalized to β-actin levels. We have averaged results from three independent experiments. (  C ) Effects of the nitrous oxide plus isoflurane treatment on TUNEL-positive cells. (  D ) Effects of the nitrous oxide plus isoflurane treatment on apoptosis. (  E ) Effects of the nitrous oxide plus isoflurane treatment on BACE levels. (  F ) Quantification of the Western blot, normalized to β-actin levels. We have averaged results from three independent experiments. (  G ) Effects of nitrous oxide plus isoflurane treatment on Aβ40 levels. We have averaged results from ten independent experiments. Aβ=β-amyloid protein; APP = amyloid precursor protein; BACE =β-site amyloid precursor protein-cleaving enzyme; FL = full-length; TUNEL = terminal deoxynucleotidyl transferase dUTP nick end labeling. *  P < 0.05; **  P < 0.01.