[BRL-44408 maleate, the antagonist of α-adrenoceptor, attenuates endogenous lipopolysacchride-induced acute lung injury through inhibiting the mitogen-activated protein kinase kinase/extracellular regulated protein kinases signaling pathway in mice].

作者信息

Lyu Xiangpeng, Cong Zhukai, Tao Yifan, Li Dan, Zhu Xi

机构信息

Department of Critical Care Medicine, Peking University Third Hospital, Beijing 100191, China (Lyu XP, Cong ZK, Li D, Zhu X); Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China (Tao YF). Corresponding author: Zhu Xi, Email:

出版信息

Zhonghua Wei Zhong Bing Ji Jiu Yi Xue. 2018 Feb;30(2):101-106. doi: 10.3760/cma.j.issn.2095-4352.2018.02.002.

DOI:10.3760/cma.j.issn.2095-4352.2018.02.002

PMID:29402356

Abstract

OBJECTIVE

To explore the effects and mechanism of α-adrenergic receptor (α-AR) antagonist BRL-44408 maleate on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice.

METHODS

Sixty male C57BL/6 mice were randomly divided into three groups (n = 20): sham group, LPS group and BRL-44408 maleate pre-treated group (BRL+LPS group). The model of ALI was replicated by intratracheally administrated of LPS (5 mg/kg), and the mice in the sham group were received an equal volume of saline. Mice in the BRL+LPS group were treated with additionally BRL-44408 maleate (5 mg/kg, i.p) at 4 hours before LPS administration. The mice were sacrificed at 6 hours and 24 hours after LPS administration in each group. Among them, 5 mice were used to collect the bronchoalveolar lavage fluid (BALF) and the other 5 mice were sacrificed for lung tissues. The levels of norepinephrine (NE), tumor necrosis factor-α (TNF-α), interleukins (IL-6, IL-10) in BALF were measured by enzyme linked immunosorbent assay (ELISA). The level of protein in BALF was measured by bicinchoninic acid (BCA) method. The histopathological changes and wet/dry (W/D) ratio of lung tissue were observed. The expression of lung phosphorylated mitogen-activated protein kinase kinase (p-MEK) and phosphorylated extracellular regulated protein kinases (p-ERK) were detected by Western Blot.

RESULTS

Compared with the sham group, the lung histopathological injury was significantly aggravated, and the histopathological injury score was significantly increased, the lung W/D ratio, and total protein content, NE, TNF-α, IL-6, IL-10 in BALF, and p-MEK and p-ERK expressions were significantly increased in LPS group at 6 hours after model setup [the lung histopathological injury score: 0.70±0.04 vs. 0.14±0.13, W/D ratio: 4.79±0.15 vs. 4.35±0.17, protein content (g/L): 1.51±0.36 vs. 0.46±0.13, NE (ng/L): 85.02±11.28 vs. 47.18±10.30, TNF-α (ng/L): 186.61±21.93 vs. 9.18±2.86, IL-6 (ng/L): 193.45±26.54 vs. 13.58±2.54, IL-10 (ng/L): 113.46±31.23 vs. 25.66±9.41, p-MEK/β-actin: 0.246±0.019 vs. 0.178±0.030, p-ERK/β-actin: 0.257±0.013 vs. 0.175±0.014, all P < 0.05], and increase with time after model setup. Compared with the LPS group, BRL-44408 maleate pretreatment for 6 hours could significantly improve the degree of lung injury and reduce the lung histopathological injury score (0.61±0.05 vs. 0.70±0.04), reduce lung W/D weight ratio (4.51±0.22 vs. 4.79±0.15); the expression of NE, TNF-α, IL-6 in BALF were inhibited [NE (ng/L): 55.77±15.86 vs. 85.02±11.28, TNF-α(ng/L): 54.79±12.68 vs. 186.61±21.93, IL-6 (ng/L): 67.66±20.08 vs. 193.45±26.54], in addition, the up-regulation of p-MEK, p-ERK were significantly inhibited (p-MEK/β-actin: 0.204±0.008 vs. 0.246±0.019, p-ERK/β-actin: 0.186±0.024 vs. 0.257±0.013), with statistically significant differences (all P < 0.05). The protein content and the expression of IL-10 in BALF showed no significant difference.