Influences of inhaled tobacco smoke on the senescence accelerated mouse (SAM)

We studied the influences of inhaled tobacco smoke on lung structure, biochemical changes in bronchoalveolar lavage (BAL) fluid, and glutathione (GSH) content of the lung in the senescence accelerated mouse (SAM), using 30 female SAM-P/8 as the "senescence-prone series", compared with SAM-R/1 as the "senescence-resistant series". At 18 wks of age, half of each series were housed in Hamburg II machines and exposed to an atmosphere of tobacco smoke for 5 wks, 10 min a day, 5 days a wk. At 24 wks of age, all of the animals were sacrificed. Blood, lung, liver, kidney and eyes were removed and the contents of GSH and thiol group (-SH) were measured (n = 5). We also performed BAL, to determine its total protein, albumin, and fibronectin contents, and elastase-like activity, elastase inhibitory capacity (EIC), and trypsin inhibitory capacity (TIC) (n = 5). Histological changes of the lungs from non-lavaged animals were also examined by light microscopy (n = 5). In SAM-P/8 not exposed to tobacco smoke, the mean linear intercept was longer than that in SAM-R/1. The exposure of SAM-P/8 to tobacco smoke caused increases in its lung weight and the ratio of albumin to total protein in BAL fluid, a decrease in the EIC/TIC ratio in BAL fluid, and a decrease in the GSH content and the GSH/-SH ratio of the lung, compared with those not exposed. We also observed focal infiltration of macrophages into alveoli with hyaline membrane and thickened alveolar wall in SAM-P/8 with tobacco exposure.(ABSTRACT TRUNCATED AT 250 WORDS)