Role of Nrf2 signaling pathway in endoplasmic reticulum stress response during lipopolysaccharide-induced acute lung injury in mice / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of nuclear factor erythroid 2-related factor 2 ( Nrf2 ) signaling pathway in endoplasmic reticulum stress response during lipopolysaccharide ( LPS)-induced acute lung injury ( ALI) in mice. Methods Forty clean-grade healthy male C57BL∕6 mice, aged 6-8 weeks, weighing 22-26 g, were divided into 4 groups ( n=10 each) using a random number table method: control group ( group C) , group ALI, salubrinal group ( group S) and salubrinal plus brusatol group ( group S+B) . Animals were intratracheally instilled with 5 mg∕kg of LPS diluted in normal saline to establish the model of ALI. Animals were intratracheally instilled with 100 μl of normal saline in group C. Mice in group S were intraperitoneally injected with endoplasmic reticulum stress response inhibitor 1 mg∕kg salubrinal at 1 and 24 h after LPS instillation. Mice of group S+B were intraperitoneally injected with brusatol 2 mg∕kg once every other day for 10 days prior to LPS instillation, and the other treatments were similar to those previously de-scribed in group S. Mice were sacrificed at 48 h after LPS administration, and lungs were removed for mi-croscopic examination of the pathological changes of lung tissues which were scored and for determination of contents of IL-17A, tumor necrosis factor-alpha ( TNF-α) and interleukin-6 ( IL-6) in lung tissues ( by en-zyme-linked immunosorbent assay) and expression of Nrf2, CCAAT∕enhancer-binding protein homologous protein (CHOP) and caspase-12 in lung tissues (by Western blot). Lung water content was calculated. Results Compared with group C, the lung water content and contents of IL-17A, TNF-α and IL-6 were significantly increased, the expression of CHOP and caspase-12 in cytoplasma was up-regulated, and the ex-pression of Nrf2 in nuclei was down-regulated in ALI and S+B groups, and the lung water content and con-tents of IL-17A, TNF-α and IL-6 were significantly increased, the expression of Nrf2 in nuclei and CHOP in cytoplasma was up-regulated, and the expression of caspase-12 was down-regulated in group S ( P<0. 05) . Compared with group ALI, the lung water content and contents of IL-17A, TNF-α and IL-6 were significantly decreased, the expression of CHOP and caspase-12 in cytoplasma was down-regulated, the ex-pression of Nrf2 in nuclei was up-regulated ( P<0. 05) , and the pathological changes were significantly at-tenuated in group S. Compared with group S, the lung water content and contents of IL-17A, TNF-α and IL-6 were significantly increased, the expression of CHOP and caspase-12 in cytoplasma was up-regulated, the expression of Nrf2 in nuclei was down-regulated ( P<0. 05) , and the pathological changes of lung tis-sues were accentuated in group S+B. Conclusion Nrf2 signaling pathway is involved in the process of en-doplasmic reticulum stress response during LPS-induced ALI in mice.