Alterations of gene expression profiles induced by sulfur dioxide in rat lungs

Abstract

Sulfur dioxide (SO2) is a ubiquitous air pollutant, presents in low concentrations in urban air and in higher concentrations in working environment. Few data are available on the effects of being exposed to this pollutant on the molecular mechanism, although some biochemical changes in lipid metabolism, intermediary metabolism and oxidative stress have been detected. The present investigation aimed at analyzing the gene expression profiles of the lungs of Wistar rats short-term (20 ppm, 6 h/day, for seven days) and long-term (5 ppm, 1 h/day, for 30 days) exposed to SO2 by Affymetrix GeneChip (RAE230A) analysis. It was found that 31 genes, containing 18 known genes and 13 novel genes, were up-regulated, and 31 genes, containing 20 known genes and 11 novel genes, were down-regulated in rats short-term exposed to SO2 compared with control rats. While there were 176 genes, containing 82 known genes and 94 novel genes, were up-regulated, and 85 genes, containing 46 known genes and 39 novel genes, were down-regulated in rats long-term exposed to SO2 compared with control rats. It is suggested that: (1) SO2 exerts its effects by different mechanisms in vivo at high-dose short-term inhalation and at low-dose long-term inhalation; (2) a notable feature of the gene expression profile was the decreased expression of genes related to oxidative phosphorylation in lungs of rats short-term exposed to SO2, which shows high-dose short-term exposed to SO2 may cause the deterioration of mitochondrial functions; (3) discriminating genes in lungs of rats long-term exposed to SO2 included those involved in fatty acid metabolism, immune, inflammatory, oxidative stress, oncogene, tumor suppresser and extracellular matrix. The mechanism of low-dose long-term exposed to SO2 is more complex.