Eosinophilic Lung Inflammation in Particulate-Induced Lung Injury. Technical Consideration in Isolating RNA for Gene Expression Studies

Particulate and other pollutant exposures are associated with lung injury and inflammation. The purpose of this study was to develop an approach by which intact RNA could be obtained from inflamed lung tissue from particulate-exposed animals in order to correlate injury with specific gene expression. Male Sprague Dawley (SD) and Fischer-344 (F-344) rats were intratracheally instilled with saline or residual oil fly ash (ROFA) particles, 8.3 mg/kg body weight in saline. At various time points following ROFA instillation, lungs were either lavaged or used for RNA isolation. ROFA exposure produced an increase in bronchoalveolar lavage fluid (BALF) neutrophils in both SD and F-344 rats. A lime-dependent increase in eosinophils occurred only in SD rats but not in F-344 rats. Extraction of inflamed pulmonary tissue having a high influx of eosinophils for RNA using the conventional acid guanidinium thiocyanate phenol-chloroform (AGPC) procedure failed to provide undegraded RNA suitable for RT-PCR and Northern bl...