Gene expression in rat right ventricles during chronic pulmonary embolism

Pulmonary vascular occlusions due to thromboemboli can result in pulmonary hypertension and right heart damage. Treatments to clear the vascular obstructions such as i.v. heparain or thrombolytics can resolve the hypertension but right ventricular damage often occurs first. Methods of protecting the right ventricle from hypertensive damage during the course of acute treatment to clear the thromboemboli are needed. Monocyte- and neutrophil-mediated inflammation and fibrosis are associated with chronic right ventricular damage but the pathways involved are not understood. A comprehesive survey of gene expression during chronic pulmonary embolism verses control rats has been conducted in this study. Pulmonary thromoembolism was simulated by injecting rats with 25-micron polystyrene microspheres into the right jugular vein. A dose of 2 million microspheres per 100 grams rat weight was used to generate chronic pulmonary embolism (~350 gram rats; injections ware 0.15 ml/100 gram of a 13 million microsphere per ml suspension in sterile 0.01% Tween-20). Control rats were injected with 0.01 ml/100 grams of Tween-20 "vehicle". After 6 weeks of PE or control, rats were euthanized and hearts surgically excised. Hearts were briefly perfused with buffer to remove blood. Right venticles were removed from whole hearts and separated into "apex" and "outflow-tract" (base) sections. Tisssues were then processed for RNA. More complete descriptions of these methods are available in PMID: 18430806, PMID: 18025228 and PMID: 16814320.