TNF-α和IκBα在内毒素致新生大鼠肺出血中的作用研究(英文)

Effects of Tumor Necrosis Factor α and IκBα on Pulmonary Hemorrhage of Neonatal Rats Induced by Lipopolysaccharide

摘要:

目的：探讨肿瘤坏死因子-α(TNF-α)和核因子-κB抑制 蛋白α(IκBα)在内毒素脂多糖(LPS)致新生大鼠肺出血发生机制中的作用。方法：将48只7～10日龄Wistar大鼠分为LPS组和生理盐水(NS)组。LPS组腹腔注射LPS 5 mg/kg，按LPS⑸浜蠊鄄斓氖奔浞治0 min，1 h，2 h，4 h，8 h，16 h和24 h组，每组6只；NS组腹腔注射等量生理盐水作为对照。对鼠肺进行大体和光镜观察，分别采用酶联免疫 吸附(ELISA)、反转录聚合酶链反应(RT-PCR)和Western Blot杂交法动态观察肺组织TNF-α蛋白和mRNA表达及IκBα表达的变化。结果：LPS注射后1 h可引起新生 大鼠明显的肺出血及炎性改变。肺组织TNF-α蛋白含量从LPS注射后1 h增加，2 h达高峰； TNF-α mRNA的表达从LPS注射后 0.5 h 明显增强(P<0.01)，2 h达高峰；而I κBα于LPS注射后 1 h 起表达很快减弱，明显低于NS组(P<0.05)，8 h表达最 弱(P<0.01)。结论：LPS可致新生大鼠肺出血。新生大鼠肺出血可 能与肺组织IκBα蛋白表达减弱，导致NF-κB活化、TNF-α基因转录上调及蛋白合成增加有关。

Abstract:

OBJECTIVE: To investigate the effects of tumor necrosis factor α (TNF α) and inhibitor protein of nuclear factor κB (IκBα) on pulmonary hemorrhage (PH) of neonatal rats induced by lipopolysaccharide (LPS). METHODS: Seven to ten days old Wistar rats were randomly separated into 2 groups: LPS group, the rats of which were injected with LPS intraperitoneally at the dosage of 5 mg/kg, and they were sacrificed 30 min, 1, 2, 4, 8, 16 and 24 hs after injection of LPS, respectively; normal saline (NS) group, where equal amount of NS was injected intraperitoneally. The number of each time point was 6. The lungs of the rats were examined by eyes and microscope. The protein and mRNA of TNF α in the lung tissues were detected by the method of ELISA and reverse transcription polymerase chain reaction. The expression of IκBα protein was measured by Western Blot. RESULTS: One hour after administration of LPS, patch like bleeding was observed in more than two lobes of the lung. From the 1st h after injection of LPS, TNF α protein increased and was significantly higher than that of NS control group (P< 0.01 ), it peaked at the 2nd h. TNF α mRNA increased 30 min after injection of LPS and was significantly higher than NS control (P< 0.01 ) and the peak was reached 2 hs after injection of LPS. The expression of IκBα quickly weakened from the 1st h after injection of LPS (P< 0.05 ), it was the lowest at the 8th h. CONCLUSIONS: LPS may lead to lung hemorrhage in the neonatal rats, which may be associated with the decrease of IκBα protein in the lung tissue and activation of NF κB, up regulation of the transcription of TNF α gene.