Nonylphenol and Octylphenol Differently Affect Cell Redox Balance by Modulating the Nitric Oxide Signaling

Figure 5

(a) Oxygen consumption rate. The respiratory rate of 3 × 10⁶ HepG2 cells was monitored after 24 h incubation with OP and NP. Digitonin (dig) was added to permeabilise cells and allow the delivery of the compounds added along the trace. The specific ETC complex activity has been evaluated upon the consecutive substrate/inhibitor addition as follows: pyruvate and malate (pyr/mal); ADP; rotenone (rot); succinate (suc); antimycin A (ant a); and ascorbate plus N,N,N,N-tetramethyl-p-phenylenediamine (Asc/TMPD). The respiratory control ratio (RCR) was determined as the O₂ consumption rate measured at the ADP addition step over the rate measured at pyr/mal step. Data values are the means ± SEM; . values were considered statistically significant by ANOVA. (b) Mitochondrial membrane potential. The fluorescence intensity of the mitochondrial-imported probe JC-1 has been measured by cytofluorimetric analysis and reported as the ratio between the red (aggregates) and green (monomer) fluorescent signal (data ± SEM, ). values were considered statistically significant by ANOVA.

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