Proteomics Studies On Lung Tissues Of Rats Exposed To Cigarette Smoke And Radon

Objective: Proteomic analysis of the rat lung tissues was conducted upon exposure to cigarette smoke and radon to provide experimental data for evaluating health risks and exploring potential molecular markers.Methods: (1) Wistar rats were exposed to cigarette smoke in a gas inhalation chamber with the smoke concentration controlled at the range of (20±5)% and oxygen concentration at 21%, twice a day, 30min each at low, middle and high dose for 1, 2 and 4 months with 5 per group. (2) Wistar rats were exposed to radon with a multifunction ecological radon room at a constant level of 1×105Bq/m3. The low, middle and high dose groups were exposed up to a cumulative dose of 100, 200 and 400WLM (working level months) respectively. The control rats were housed in a room with a background concentration of radon at 80 Bq/m3. (3) Wistar rats were exposed to radon for up to cumulative dose of 200 WLM and cigarette smoke for 2 months in the same conditions as (1) and (2) as the joint group. (4) Pathological changes in lung tissue of the rats were observed and the contents of the radon daughter - 210Po in rats were determined. (5) Two-dimensional electrophoresis (2-DE) was used to separate proteins from rats. (6) The differential expression proteins were identified by MALDI-TOF MS or MALDI-TOF-TOF MS. The results were searched in NCBInr database. (7) The differential expression proteins of RAGE, Trx and S100A6 were verified by immunohistochemistry and western blot.Results: (1) Pathological changes in the lung tissues were observed with findings of inflammatory cell penetrated into mucous membrane, pulmonary edema, hyperaemia in the alveolus interval, fibrosis and so on. The contents of 210Po in rats exposed to radon increased with the exposure dose. (2) 2-DE technique resulted in 450 proteins at condition of pH3~10, 11cm IPG strip, 625 proteins at pH3~10, 24cm IPG strip and 1248 proteins at pH4~7, 24cm IPG strip which was chosen for later experiment. (3) 18 differential expression proteins were found in the lung of rats exposed to cigarette smoke, with 10 up and 8 down-regulated expression proteins. 15 differential expression proteins were identified in the lung of rats exposed to radon, with 9 up and 6 down-regulated expression proteins. 20 differential expression proteins were identified in the lung of rats exposed to cigarette smoke and radon, with 12 up and 8 down-regulated expression proteins. These proteins were functioned in energy metabolism, proliferation, antioxidant, signal transduction, cytoskeleton, and so on. (4) The proteins of RAGE, Trx and S100A6 were confirmed by immunohistochemistry and western blot, which were consistent with the 2-DE results.Conclusions: (1) The animal models of cigarette smoke and radon exposure were set up and a 2-DE proteomic approach was established. (2) Differential expression proteins were identified with functions involved in energy metabolism, proliferation, antioxidant, signal transduction and cytoskeleton, indicating a multistep process in response to cigarette smoke and radon exposure. (3) Proteins of RAGE, Trx and S100A6 could be applied as potential molecular markers in evaluating adverse effects induced by cigarette smoke and radon exposure.