The effect of lead exposure on tracheal responsiveness to methacholine and ovalbumin, total and differential white blood cells count, and serum levels of immunoglobulin E, histamine, and cytokines in guinea pigs

The effect of exposure to inhaled lead acetate in guinea pigs was evaluated. The present study comprised of five groups of guinea pigs including control (C), sensitized to ovalbumin (OA; S) and three groups exposed to 0.1, 0.2, and 0.4M inhaled lead (Pb; n=6 for each group). Tracheal responsiveness to methacholine and OA, total and differential white blood cells (WBCs) count in lung lavage, serum levels of cytokines (interferon (IFN-) and interleukin 4 (IL-4)), histamines, and immunoglobulin E (IgE), and Pb concentration in lung were measured. Tracheal responsiveness to methacholine, OA, total and differential WBC types as well as IL-4, IFN-, histamine, and IgE were significantly increased but IFN-/IL-4 were significantly decreased in sensitized animals as well as those exposed to high Pb concentrations when compared with the control group (from p<0.05 to p<0.001). In addition, there was not a significant difference in most measured values between animals exposed to high Pb concentration and group S. The Pb concentration in lung tissues of animals exposed to all three Pb concentrations was significantly higher than that of group C (p<0.001 for all cases).These results showed that inhaled lead acetate exposure can induce lung inflammatory changes similar to sensitized animals. Therefore, exposure to environmental Pb pollution may cause asthma-like changes.