Effects of inflammatory mediators and mechanism of dynamic factors on lung injury in a dog model of a-cute respiratory distress syndrome / 中华急诊医学杂志

ABSTRACT

Objective To evaluate the effect on inflammatory mediators and mechanism of dynamic factors on lung injury in a dog model of acute respiratory distress syndrome (ARDS). Method The ARDS dog model was duplicated by instillation hydrochloric acid. The dogs were randomly (random number) divided into six groups (1) normal control group (N group); (2) ARDS group (M group); (3) low VT (6 mL/kg) at respiratory rate 30, low inspiratory flow 6 mL/(kg·s). (4) large VT (20 mL/kg) at respiratory rate 30, high inspiratory flow 20 mL/kg·s.(5) large VT (20 mL/kg) at respiratory rate 15, high inspiratory flow 17 mL/(kg·s). (6) large VT (20 mL/kg) at respiratory rate 15, low inspiratory flow 10 mL/(kg·s). All the dogs were killed after 4 h ventilation. TNF-α、IL-8, p38 MAPK and NF-κB activity in the lung were measured. Results The expression of IL-8 protein in B and C groups was much higher than that of other groups ( P < 0.01) . There was no significant difference among M, A and D groups (P > 0.05). The gray scale ratio of B group was obviously higher than that of other groups (P < 0.01), except C group (P > 0.05). There was no significant changes among M, A and D groups in TNF-α protein contents. p38 MAPK value of positive staining of B group was the strongest, significantlyhigher than that of D group ( P < 0.01) .The expression of p38 MAPK in B and C groups was much higher than other groups (P <0.01). NF-κB activity in B group (33.56±2.85%) was significantly higher than that in A (10.35±0.6%)、D(7. 11 ± 0.47%)group, but there was no difference between B and C group (30.87 ± 1.16%). Conclusions Ventilation at high tidal volume, high inspiratory flow rate, high respiratory rate could activate p38 MAPK and increase the activity of NF-κB with the result of aggravating the release of inflammatory mediators. p38 MAPK and NF-κB activation are the major mechanisms in the development of VILI.