Tissue levels of malondialdehyde after passive smoke exposure of rats for a 24-week period.

The present study was to evaluate the effects of chronic cigarette smoke exposure on lipid peroxidation in various organ tissues. Sprague-Dawley rats were exposed to passive smoking 2 hr per day, 6 days per week (Monday-Saturday), for 24 weeks. Malondialdehyde levels, as an index of lipid peroxidation, were measured by the thiobarbituric acid assay. Levels were significantly higher in tissues of passive-smoke-exposed groups (n=10) compared with normal-bred control groups (n=6), for red blood cells (2.17+/-0.22 vs. 1.80+/-0.39 nmol/mg), lung (1.39+/-0.32 vs. 1.03+/-0.35 nmol/mg), and spleen (1.75+/-0.33 vs. 1.42+/-0.15 nmol/mg); p<.05. No differences in malondialdehyde levels were found in plasma, heart, liver, stomach, and renal tissues. The results suggest that chronic environmental tobacco smoke exposure can increase lipid peroxidation in red blood cells and in lung and spleen tissue. This finding brings further investigative attention to the public health issue of the injurious effects of chronic passive smoke exposure.