Selenium pretreatment preserves mitochondrial respiratory chain complex activities following hypoxia. A. A typical recording of oxygen consumption of digitonin permeabilized cells showing oxygen concentration (blue) and respiration (oxygen flux, red) using multiple substrates-inhibitor analysis. The activity of each complex was calculated from the difference in reduction in oxygen content in the presence of specific substrate and specific inhibitor. B-D. Activity of each mitochondrial complex (1, II, +III and IV) indicates the inhibition of hypoxia-suppressed complex activities by selenium pretreatment. Data represents means ± SD. **P < 0.01, ***P < 0.001 vs. control and ##p < 0.01, ###p < 0.001 vs. respective group. Se = selenium, Cont = control and Hypo = hypoxia. AA, antimycin A; As, ascorbate; Cyto C, cytochrome c; GM, glutamate and malate; Rot, rotenone; Sc, succinate; TMPD, N,N,N’,N’-tetramethyl-p-phenylenediamine dihydrochloride.