糖皮质激素对高氧诱导新生大鼠肺组织RAGE-NF-κB通路的影响

Effects of glucocorticoid on RAGE-NF-κB pathway in hyperoxia-induced lung tissues of neonatal rats

摘要:

目的 探讨RAGE-NF-κB 信号通路在新生大鼠高氧肺损伤过程中的变化,以及糖皮质激素对其的影响.方法 24 只新生大鼠随机分为空气对照组、高氧模型组和激素干预组.模型组新生大鼠于生后即暴露于95% 氧气浓度环境中1 周,空气对照组大鼠生后仅暴露于同室内空气中饲养7 d,激素干预组于造模后行尾静脉注射地塞米松(1 mg/kg),隔天1 次,共3 次.日龄13 d 时处死全部大鼠,RT-PCR 检测各组肺组织RAGEmRNA 及NF-κB mRNA的表达;Western blot检测RAGE 及NF-κB 蛋白水平;ELISA 法检测血清及肺泡灌洗液(BALF)中TNF-α 和sRAGE 含量;苏木精- 伊红染色后行肺组织病理学评估.结果 与对照组和激素干预组相比,高氧模型组肺组织RAGE、NF-κB 的mRNA 和蛋白表达水平均明显增高(均P<0.05),血清中sRAGE 含量明显升高(P<0.01),BALF 中sRAGE 含量下降(P<0.01);与对照组相比,激素干预组肺组织RAGE、NF-κB 的mRNA和蛋白表达水平明显升高(P<0.05),血清中sRAGE 含量明显升高(P<0.05),而BALF 中sRAGE 含量明显下降(P<0.05).结论 RAGE-NF-κB 通路在高氧诱导的新生大鼠肺损伤中活化增强,糖皮质激素可能通过下调RAGE-NF-κB 信号通路对高氧肺损伤发挥保护作用.

Abstract:

Objective To explore the change of RAGE-NF-κB signaling pathway during the course of hyperoxiainduced lung injury in newborn rats, and the effect of glucocorticoid on this pathway. Methods Twenty-four Sprague- Dawley neonatal rats were randomly divided into three groups (n=8 each): sham control (control group), hyperoxiainduced acute lung injury (model group) and glucocorticoid-treated acute lung injury (glucocorticoid group). Rats were sacrificed at 13 days after birth. RAGE and NF-κB expression levels in lung tissues were detected by reverse transcription polymerase chain reaction, Western blot and immunohistochemistry analysis. The levels of tumor necrosis factor α (TNF-α) and sRAGE in bronchoalveolar lavage fluid (BALF) and serum were measured using ELISA. Lung damage was evaluated by histological examinations. Results RAGE and NF-κB mRNA and protein expression levels in lung tissues were significantly increased in the model and glucocorticoid groups compared with the control group (P<0.05). Serum RAGE concentrations were significantly increased but RAGE concentrations in BALF were significantly reduced in the model and glucocorticoid groups compared with the control group (P<0.05). RAGE and NF-κB expression at both mRNA and protein levels in lung tissues was significantly lower in the glucocorticoid group than in the model group (P<0.05). RAGE concentrations were significantly lower in serum (P<0.05), but were higher in BALF (P<0.05) in the glucocorticoid group than in the model group. Conclusions RAGE-NF-κB pathway plays an important role in hyperoxia-induced lung injury in neonatal rats, and glucocorticoid administration may play a protective role against the lung injury by down-regulating RAGE-NF-κB signaling pathway.