长链非编码 RNA MALAT1 通过 p38 MAPK/p65 NF-κB 通路对脓毒症小鼠肺损伤的影响。
Influence of lncRNA MALAT1 on septic lung injury in mice through p38 MAPK/p65 NF-κB pathway.
机构信息
Department of Obstetrics and Gynecology, Xiamen Maternal and Child Health Hospital, Xiamen, China.
出版信息
Eur Rev Med Pharmacol Sci. 2019 Feb;23(3):1296-1304. doi: 10.26355/eurrev_201902_17025.
OBJECTIVE
To investigate the influence of long non-coding ribonucleic acid (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on septic lung injury in mice and its mechanism, so as to provide references for the clinical prevention and treatment of septic lung injury in the future.
MATERIALS AND METHODS
A total of 60 male C57 mice were randomly divided into Control group (n=20), lipopolysaccharide (LPS) group (n=20), and LPS+MALAT1 siRNA group (n=20) using a random number table. The mouse model of septic lung injury was established via intraperitoneal injection of LPS (10 mg/kg), and the MALAT1 knockdown model was established via tail intravenous injection of MALAT1 siRNA. After 12 h, the lung was taken to measure the wet weight/dry weight ratio. Also, the activity of myeloperoxidase (MPO) in lung tissues was detected. The number of neutrophils and macrophages in bronchoalveolar lavage fluid (BALF) was detected via bronchoalveolar lavage. Moreover, the messenger RNA (mRNA) expression levels of inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and IL-6, in lung tissues were detected via Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Finally, the expression level of p38 in lung tissues was detected via immunohistochemical staining, and the expressions of p38 mitogen-activated protein kinase (MAPK)/p65 nuclear factor-κB (NF-κB) signaling pathway-related proteins in lung tissues of mice were detected via Western blotting.
RESULTS
The expression of lncRNA MALAT1 in lung tissues of mice with septic lung injury was significantly increased (p<0.05). After knockdown of lncRNA MALAT1, the LPS-induced pathological injury of lungs could be improved, and the wet weight/dry weight ratio of lungs could be reduced (p<0.05). Compared with those in LPS group, the total number of inflammatory cells and the number of neutrophils and macrophages in BALF were significantly decreased in LPS+MALAT1 siRNA group (p<0.05), and the levels of inflammatory cytokines were also significantly inhibited (p<0.05). The immunohistochemical results manifested that the knockdown of lncRNA MALAT1 could inhibit the LPS-induced up-regulation of p38 in lung tissues in mice. According to the results of Western blotting, the p38 MAPK/p65 NF-κB signaling pathway was significantly activated in lung tissues in LPS group (p<0.05), while it was significantly suppressed after inhibition on lncRNA MALAT1 (p<0.05).
CONCLUSIONS
The knockdown of lncRNA MALAT1 can significantly improve the septic lung injury in mice, whose mechanism may be related to its inhibition on the p38 MAPK/p65 NF-κB signaling pathway.
目的
研究长链非编码 RNA（lncRNA）转移相关肺腺癌转录本 1（MALAT1）对脓毒症肺损伤小鼠的影响及其机制，为今后脓毒症肺损伤的临床防治提供参考。
材料与方法
采用随机数字表法将 60 只雄性 C57 小鼠随机分为对照组（n=20）、脂多糖（LPS）组（n=20）和 LPS+MALAT1 siRNA 组（n=20）。通过腹腔注射 LPS（10 mg/kg）建立脓毒症肺损伤小鼠模型，通过尾静脉注射 MALAT1 siRNA 建立 MALAT1 敲低模型。12 h 后取肺，测量湿重/干重比。同时，检测肺组织髓过氧化物酶（MPO）活性。通过支气管肺泡灌洗检测支气管肺泡灌洗液（BALF）中中性粒细胞和巨噬细胞的数量。此外，通过逆转录-聚合酶链反应（RT-PCR）检测肺组织中炎症细胞因子肿瘤坏死因子-α（TNF-α）、白细胞介素-1（IL-1）和白细胞介素-6（IL-6）的 mRNA 表达水平。最后，通过免疫组织化学染色检测肺组织中 p38 的表达水平，通过 Western blot 检测肺组织中 p38 丝裂原活化蛋白激酶（MAPK）/p65 核因子-κB（NF-κB）信号通路相关蛋白的表达。
结果
脓毒症肺损伤小鼠肺组织中 lncRNA MALAT1 的表达明显增加（p<0.05）。敲低 lncRNA MALAT1 后，可改善 LPS 诱导的肺组织病理损伤，降低肺组织湿重/干重比（p<0.05）。与 LPS 组相比，LPS+MALAT1 siRNA 组 BALF 中总炎性细胞数及中性粒细胞和巨噬细胞数明显减少（p<0.05），炎症细胞因子水平也明显抑制（p<0.05）。免疫组织化学结果表明，敲低 lncRNA MALAT1 可抑制 LPS 诱导的小鼠肺组织中 p38 的上调。Western blot 结果显示，LPS 组肺组织中 p38 MAPK/p65 NF-κB 信号通路明显激活（p<0.05），抑制 lncRNA MALAT1 后明显受到抑制（p<0.05）。
结论
敲低 lncRNA MALAT1 可显著改善脓毒症肺损伤小鼠的肺损伤，其机制可能与其抑制 p38 MAPK/p65 NF-κB 信号通路有关。
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