地塞米松对重症胎粪吸入新生兔环氧化酶水平的影响

摘要

Objective To observe the effect of dexamethasone on Cyclooxygenase in newborn rabbits with severe meconium aspiration syndrome. Methods Twenty four newborn rabbits were divided randomly into control group, saline group and dexamethasone group. Meconium solutions were injected into the endotracheal tube by 4 ml/kg in the two groups. Dexamethasone group intravenous injection of dexamethasone 0. 5 mg/kg at two doses 1h and 3h after meconium solutions instilled, Saline group received an equal volume of saline at the same points of time. All rabbits of three groups used proportional assist ventilation in order to maintain normal range of tidal volume (4-10mi/kg) and normal oxygen saturation (85% or more), The rabbits were killed at 8h after meconium instillation,lungs and trachea were excised. The Cyclooxygenase was tested by enzyme-link immunosorbent assay(ELISA) which in bronchoalveolar lavage fluid(BALF) and lung homogenate, and compared among three groups. Results Among the three groups, there was no statistically significant difference in bronchoalveolar lavage fluid and lung homogenate ( P ＞ 0. 05 ) levels of cyclooxygenase-1. Compared the levels of cyclooxygenase-2 in control group, saline group and dexamethasone group, in bronchoalveolar lavage fluid[( 1.07 ±0. 84) μg/L, (3.98 +0.54) μg/L, (2.58 +0.43)μg/L] the differences were significant ( P ＜ 0.05 ), in lung homogenate [( 1.22 ± 0. 77) μg/L, (6. 14 + 0. 18) μg/L,(5.33 + 0. 57) μg/L], the differences were significant ( P ＜ 0.05 ). Conclusion Dexamethasone inhibites the expression of COX-2, alleviates the lungs inflammation which is caused by meconium aspiration.%目的 观察地塞米松对重症胎粪吸入新生兔环氧化酶水平的影响.方法 将24只新生兔完全随机分为空白组、生理盐水组、地塞米松组,每组8只.空白组气管插管后不灌胎粪;后2组气管插管后注入胎粪混合物,地塞米松组在胎粪灌入后1和3 h静脉注射地塞米松,生理盐水组在同时间静脉注射等量生理盐水.3组均比例辅助通气模式机械通气,以维持正常潮气量、正常血氧饱和度及正常血气值,8 h后处死,取肺泡灌洗液,制备肺组织匀浆,用酶联免疫吸附法检测环氧化酶的含量.结果 3组间肺泡灌洗液和肺组织匀浆中环氧化酶I含量比较,差异均无统计学意义(均P＞0.05).空白组、生理盐水组、地塞米松组动物,肺泡灌洗液中环氧化酶2含量分别为(1.07±0.84)、(3.98±0.54)、(2.58±0.43)μg/L,肺组织匀浆中分别为(1.22±0.77)、(6.14±0.18)、(5.33±0.57)μg/L,3组间两两比较,差异亦均有统计学意义(均P＜0.05).结论 地塞米松可抑制环氧化酶2的表达,减轻胎粪吸入导致的肺部炎症反应.