Proteome changes in auricular lymph nodes and serum after dermal sensitization to toluene diisocyanate in mice

Introduction. Some reactive chemicals, such as diisocyanates, are capable of initiating an allergic response, which can lead to occupational asthma after a latency period. Clinical symptoms such as cough, wheezing and dyspnea occur only late, making it difficult to intervene at an early stage. So far, most studies using proteomics in lung research have focused on comparisons of healthy vs. diseased subjects. Here, using two-dimensional difference gel electrophoresis (2D-DIGE), we explored proteome changes in the local draining lymph nodes and serum of mice dermally sensitized once or twice with toluene diisocyanate (TDI) before asthma is induced to explore biomarkers of sensitization. Methods. The proteomes of male BALB/c mice (6 weeks old, 20g), sensitized once (n=12) or twice (n=12) with 0.3% TDI, were individually compared with control mice (n=12) in two separate experiments using 2D-DIGE and Decyder 7.0. A commercially available ELISA kit was used to validate the difference in hemopexin levels between TDI-sensitized and control mice. Western blotting was used to validate the results of lymphocyte specific protein 1 and coronin 1a levels. GAPDH was used as an internal standard in Western blot validation experiments. Graphpad Prism 4.01 (Graphpad Software Inc) was used for statistical analysis of ELISA and Western blot data. All data were normally distributed (tested using Kolmogorov-Smirnov). An unpaired t-test was used to compare both groups (AOO vs. TDI). A level of p