OBJECTIVETo determine the lung expression of tissue factor (TF) mRNA in hepatopulmonary syndrome (HPS) using a rat model system and to investigate the potential significance of its differential expression.

METHODSForty male Sprague-Dawley rats were used to establish models of cirrhosis (n = 20) and HPS (n = 20). Blood gas analysis was used to investigate the effects of each model on pulmonary function. Effects on the expression of TF mRNA in lung were determined by qRT-PCR and on lung pathology by histological analysis.

RESULTSThe HPS rats showed significantly lower PaO2 than the cirrhosis rats (58.20 +/- 3.19 mmHg vs. 85.00 +/- 2.53 mmHg, P less than 0.05) but significantly higher TF mRNA expression in lung (0.77 +/- 0.22 vs. 0.33 +/- 0.14, P less than 0.05). TF mRNA expression was negatively correlated with the value of PaO2 (r = -0.565, P less than 0.05). The lungs of the cirrhosis rats showed widened alveolar intervals, diversified sizes of alveolar spaces, reduced lung capacity, inflammatory cell infiltration, and hyperemia in the pulmonary vessels. The lungs of the HPS rats showed all of the same changes but also with accumulated macrophages and micro-thrombosis in the pulmonary vessels. Among the HPS rats, those with micro-thrombosis in pulmonary vessels showed a greater increase in TF mRNA expression than those without (0.68 +/- 0.17 vs. 0.40 +/- 0.12, P less than 0.05).

CONCLUSIONThe expression of TF mRNA in lung of hepatopulmonary syndrome model rats was elevated and might increase the incidence of thromboembolism in the lung.