Fig. 1. Two percent isoflurane induces caspase-3 activation, decreases the levels of amyloid precursor protein C-terminal fragments (APP-CTFs), and increases amyloid β protein (Aβ) levels in H4 amyloid precursor protein full-length (APP-FL) cells. ( A ) The 2% isoflurane treatment ( lanes 4–6 ) induces caspase-3 cleavage (activation) as compared with control conditions ( lanes 1–3 ) in H4-APP-FL cells. There is no significant difference in the amounts of β-actin in the control conditions or 2% isoflurane–treated H4-APP-FL cells. ( B ) The 2% isoflurane treatment ( black bar ) increases caspase-3 activation compared with control conditions ( white bar ), normalized to β-actin levels. ( C ) Cell viability assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) study in H4-APP-FL cells. The 2% isoflurane treatment ( black bar ) decreases cell viability as compared with control conditions ( white bar ) in H4-APP-FL cells. ( D ) The 2% isoflurane treatment ( lanes 3 and 4 ) renders a visible reduction in APP-CTF levels as compared with control conditions ( lanes 1 and 2 ). ( E ) Quantitation of the Western blot shows that 2% isoflurane treatment ( black bar ) decreases the ratio of APP-CTFs to APP-FL as compared with control conditions ( white bar ), normalized to β-actin levels, in H4-APP-FL cells. ( F ) Two percent isoflurane ( black bar ) increases both Aβ40and Aβ42levels as compared with control conditions ( white bar ) in H4-APP-FL cells. Data are mean ± SD; n = 9–10 for each experimental group. A t test is used to compare the difference between control conditions and the 2% isoflurane treatment condition: * P < 0.05, ** P < 0.01.