Objective: To investigate the effects of high frequency oscillatory ventilation (HFOV) and its combination with administration of pulmonary surfactant (PS) on inflammatory response of lung tissue in rabbits with inhalation injury.
Methods: Severe steam inhalation injury models were reproduced in 24 New Zealand albino rabbits. They were divided into control group (n = 8), HFOV group (n = 8), and HFOV + PS group (n = 8) according to the random number table, and they received ventilation in metered volume, HFOV, and HFOV + PS treatment respectively. Lung tissue samples of rabbits were collected at 3.5 h after treatment for pathological inspection and pulmonary injury score, assay of the activity of myeloperoxidase (MPO) and cysteinyl aspartate-specific protease 1 (caspase-1), and the determination of the contents of TNF-alpha, IL-18, IL-10, IL-13 and their mRNA expression.
Results: Pathological change in different degree of rabbit lung tissue in each group were observed, and they were most obvious in the control group, and least in the HFOV + PS group. The lung tissue injury scores of control group, HFOV group, and HFOV + PS group was 3.71 +/- 0.43, 2.87 +/- 0.26, and 2.08 +/- 0.28 respectively. The difference between either two of them were statistically significant (P < 0.01). The MPO content and caspase-1 activity of rabbits in HFOV and HFOV + PS groups were obviously lower than those in control group (P < 0.01), and MPO content and caspase-1 activity of rabbits in HFOV + PS group were obviously lower than those in HFOV group (P < 0.05). In HFOV group and HFOV + PS group, the contents of TNF-alpha, IL-18 and their mRNA expression in lung tissue homogenates were obviously lower than those in control group (P < 0.01); while the contents of IL-10, IL-13 and their mRNA expression were obviously higher than those in control group (P < 0.01). Changes in these contents and expression in HFOV + PS group were more obvious than those in HFOV group (P < 0.05).
Conclusions: HFOV can alleviate inflammatory response in rabbit lung tissue and pulmonary injury induced by inhalation injury, and the effect is more obvious when combined with PS.