Role of HO-1 in endotoxin-induced acute lung injury in mice: relationship with regulation of mitochondrial quality control / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of heme oxygenase-1 (HO-1) in endotoxin-induced acute lung injury (ALI) and the relationship with the regulation of mitochondrial quality control in mice.Methods:Clean-grade healthy male adult C57BL/6 mice, aged 6-8 weeks, weighing 20-25 g, were selected.HO-1 inducible gene knockout mice (HO-1 -/-) were prepared based on CRISPER/Cas9-mediated EGE system, and HO-1 gene overexpression mice (HO-1 + /+ ) were prepared by transfection of HO-1 overexpressed adenovirus vector.The mice were divided into 2 groups ( n=6 each) using a random number table method: control group (group WT, group HO-1 -/-, group HO-1 + /+ ) and endotoxin-induced ALI group (group ALI, group HO-1 -/-+ ALI, group HO-1 + /+ + ALI). Lipopolysaccharide 15 mg/kg was injected through the tail vein to develop the model of endotoxin-induced ALI, and the equal volume of normal saline was given instead in each control group.The mice were sacrificed by bloodletting at 12 h after lipopolysaccharide or normal saline administration.The lung tissues were harvested for microscopic examination of the pathological changes which were scored, for determination of GSH and GSSG contents, for observation of the ultrastructure of mitochondria (with a transmission electron microscope) and survival within 12 h, for measurement of mitochondrial membrane potential (MMP) levels, and for determination of the expression of mitochondrial quality control-related proteins mitochondrial fusion protein 2 (Mfn2) and dynamin-related protein 1 (Drp1), peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α), nuclear respiratory factor 1 (NRF1), mitophagy marker protein PTEN-induced kinase 1 (PINK1) and E3 ubiquitin-protein ligase Parkin.The ratio of GSH/GSSG was calculated. Results:Compared with control group (group WT, group HO-1 + /+ and group HO-1 -/-), the 12-h survival rate and MMP were significantly decreased, the lung injury score was increased, GSH content and GSH/GSSG ratio were decreased, and the content of GSSG was increased in endotoxin-induced ALI groups (group ALI, group HO-1 + /+ + ALI and group HO-1 -/-+ ALI) ( P<0.05). Compared with group ALI, the 12-h survival rate and MMP were significantly decreased, the lung injury score was increased, the GSH content and GSH/GSSG ratio were decreased, the GSSG content was increased, and the expression of HO-1, Mfn2, PGC-1α, NRF1, PINK1 and Parkin was down-regulated, and Drp1 expression was up-regulated in group HO-1 -/-+ ALI, and 12-h survival rate and MMP were significantly increased, lung injury score was decreased, GSH content and GSH/GSSG ratio were increased, GSSG content was decreased, the expression of HO-1, Mfn2, PGC-1α, NRF1, PINK1 and Parkin was up-regulated, and the expression of Drp1 was down-regulated in group HO-1 + /+ + ALI ( P<0.05). Conclusions:HO-1 is involved in the process of endotoxin-induced ALI in mice, which is related to the regulation of mitochondrial quality control.