[Effect of sustained inflation on inflammatory response of extra pulmonary organs in acute respiratory distress syndrome in rabbit].

Objective: To evaluate the influence of sustained inflation (SI) on inflammatory response of extra pulmonary organs in acute respiratory distress syndrome (ARDS) in rabbit.

Methods: The ARDS rabbit model were replicated by saline alveoli-lavage. The rabbits were randomly divided into four groups: 1. normal group; 2. ARDS group; 3. low-volume(V(T)) + best end-expiratory pressure group (LVBP): V(T) 6 ml/kg, PEEP 2 cm H(2)O(1 cm H(2)O=0.098 kPa) greater than the pressure of lower inflection point in pressure-volume curve (Pinf); 4. SI group: same settings as LVBP group plus SI performed every hour. After 4 hours of ventilation, liver and intestine homogenates were prepared to assay tumor necrosis factor (TNF)-alpha and interleukin(IL)-10 levels by enzyme-linked immunoadsorbent assay and their mRNA expression by reverse transcription-polymerase chain reaction. Myeloperoxidase (MPO) and malondialdehyde (MDA) were assessed at the same time.

Results: In SI group, TNF-alpha mRNA expression in the liver and intestine tissues (24.82+/-7.88 and 25.06+/-10.57) were decreased significantly compared with ARDS (36.88+/-6.83 and 36.48+/-8.23) and LVBP groups (42.34+/-8.55 and 37.59+/-10.63, all P<0.05). The expression of IL-10 mRNA in the liver and intestine of rabbits in SI group (17.31+/-5.72 and 10.90+/-3.30) was lower than that of ARDS (24.64+/-3.85 and 24.31+/-7.69) and LVBP group (25.03+/-9.38 and 21.83+/-7.34, all P<0.05) significantly. In SI group, the levels of TNF-alpha and IL-10 in liver and intestine tissue were similar to that of the other groups. The contents of MPO and MDA had no difference compared with the other groups too.

Conclusion: SI can down-regulate inflammatory mediator expression of extra-pulmonary organs in rabbits with ARDS, and it may inhibit the inflammatory response in extra pulmonary organs.