Fig. 2. Optical densities in the box plots are expressed as the ratio of the optical densities of total malondialdehyde (MDA)-protein adducts to those of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in each muscle. Standard box plots with median (twenty-fifth and seventy-fifth percentiles) and whiskers (at minimum and maximum values) are depicted. There was an almost significant decrease in MDA-protein adducts in the diaphragms (A ) and gastrocnemius (B ) muscles of the high-tidal volume (V^T, n = 8) rats compared with the controls (n = 8). In the soleus (C ) and tibialis anterior (D ), MDA-protein adduct levels were significantly decreased in high- and moderate-V^Trats (n = 8) compared with the controls. Representative immunoblots of MDA-protein adducts of different molecular weights (MW), in kilo Daltons, in the lungs (E ) of control, moderate-V^T, and high-V^Tmechanically ventilated rats. Optical densities in the box plots are expressed as the ratio of the optical densities of total MDA-protein adducts to those of GAPDH in the lungs (F ). Standard box plots with median (twenty-fifth and seventy-fifth percentiles) and whiskers (at minimum and maximum values) are depicted (F ). Lungs of high-V^Trats exhibited a significant increase in MDA-protein adducts compared with either controls or moderate-VT animals. The lungs of moderate-V^Trodents showed an almost significant increase in MDA-protein adducts compared with control animals (F ).