Effects of partial liquid ventilation on lipopolysaccharide-induced inflammatory responses in rats

To determine whether partial liquid ventilation (PLV) modified lung inflammatory response, we analyzed blood cytokine levels and cytokine mRNA expression in the lungs, using a rat model of endotoxemia. Thirty-six rats were allocated into one of four groups. The first group received conventional gas ventilation (CV group), the second group received 10 ml/kg perflubron intratracheally in combination with mechanical gas ventilation (PLV group), the third group received 20 mg/kg Escherichia coli lipopolyssacharide (LPS) intravenously in combination with mechanical gas ventilation (LPS group), and the fourth group received PLV and LPS (PLV + LPS group). Blood levels of TNF-alpha, IL-1beta, IL-6, IL-10, INF-gamma and IL-1 receptor antagonist were significantly increased in LPS and PLV + LPS groups. mRNA expression of pro- and anti-inflammatory cytokines in the lung tissue was also significantly increased in these groups. mRNA expression of IL-6 in PLV + LPS group was significantly increased in comparison with LPS group. Other cytokine mRNA expression including IL-10 and IL-1beta was also potentiated in PLV + LPS group, however this was not significant. Our results suggest that PLV does not protect the lungs against inflammation in systemic endotoxemia in rats.