Lack Of Effect On Rat Lung Stress-Inducible Heat Shock Protein 70 After Acute Tobacco Smoke Inhalation

Abstract

few investigations have examined in vivo expression of heat shock proteins (HSPs) and stress proteins in the lung following environmental stress. Such proteins are thought to provide cellular protection against environmental trauma. This study describes the initial effects of tobacco smoke inhalation on stress-inducible HSP 70 level in the rat lung. Specifically, the expression and possible elevation of stress-inducible HSP 70 in the rat lung was examined 5 h following inhalation of tobacco smoke from one research cigarette (2R1/University of Kentucky). Male Sprague-Dawley rats were exposed nose-only to tobacco smoke (n = 6), while control rats were exposed to purified filtered air (n = 6). Samples of the peripheral lung from the right apical lobe were homogenized and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE), protein immunoblotting, chemiluminescence detection, and computerized optical densitometric scanning. The results revealed that stressinducible HSP 70 is present constitutively in the control rat lung at 30.83 ± 14.81 (SD) optical units and is elevated slightly at 35.33 ± 12.05 (SD) optical units but not significantly (p = .77) in lungs that inhaled tobacco smoke. A more complete time-course profile will determine whether stressinducible HSP 70 levels are elevated significantly following tobacco smoke inhalation. Changes in the levels of stress proteins that are elevated in damaged lung cells may be of utility for toxi-cological assessment following inhalation exposures to either tobacco smoke or other types of pulmonary toxicants in the atmosphere.