Application of laser capture microdissection and protein microarray technologies in the molecular analysis of airway injury following pollution particle exposure

Understanding the mechanisms by which various types of air pollution particles (particulate matter, PM) mediate adverse health effects would provide biological plausibility to epidemiological associations of increased rates of morbidity and mortality. The majority of information regarding the means by which PM generates lung injury has been derived from in vitro studies. However, it is unclear as to what extent these mechanisms, can be extrapolated to the in vivo situation. Current methods to assess mechanisms of PM-induced lung injury make it difficult to obtain site-specific, sensitive, and comprehensive determinations of cellular and molecular pathology associated with PM-induced injury. In the present study, the ability of laser capture microdissection (LCM) and protein microarray technologies were assessed to examine the effect of residual oil fly ash (ROFA) exposure on airway intracellular signaling pathways and transcription factor activation. Sprague-Dawley rats were intratracheally instilled with 0.5 mg/rat of ROFA. LCM was used to recover airway cells and protein extracts derived from the microdissected airways were analyzed by protein microarray. ROFA exposure increased p-ERK:ERK and P-l κB:l κB, suggesting changes in cell growth, transformation, and inflammation within the airway. These results are consistent with previously reported in vitro findings, demonstrating for the first time the credibility of applying LCM and protein microarray technologies to assess acute lung injury induced by environmental air pollutants.