Immunohistochemistry was performed on formalin fixed tissues using 3-NT antiserum (brown) against a hemtoxylin nuclear counterstain (blue) in liver sections of control (Con) and ethanol (EtOH)-fed mice exposed to either filtered air (FA) or ETS. Panel A, There was increased 3-NT in control + ETS group (c) and the EtOH + FA group (b) compared to control diet alone (a). Increased 3-NT was observed in the EtOH + ETS group (d) with intense staining for 3-NT around the central veins. Panel B, Image analysis demonstrated increased intensity of 3-NT in liver from EtOH + ETS group compared to all other groups. Data represent the mean ± SEM for 3 pairs of mice. Magnification is 200X. *p<0.05, compared to each corresponding control; **p<0.05, compared to control + filtered air; ***p<0.05, compared to ethanol + filtered air. Two-factor ANOVA; ethanol, ETS, and ethanol × ETS, p<0.0001, ethanol, ETS.