Role of NAD +-mediated deacetylation activity of SIRT1 in endotoxin-induced acute lung injury in mice / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of nicotinamide adenine dinucleotide (NAD + )-mediated deacetylation activity of silent information regulator 1 (SIRT1) in endotoxin-induced acute lung injury (ALI) in mice. Methods:Twenty-five SPF clean-grade healthy male C57BL/6 mice including 10 wild-type (WT) and 15 NMNAT1 conditional-knockout (KO) mice, aged 6-8 weeks, weighing 20-25 g, were selected.The WT mice were divided into 2 groups ( n=5 each) using a random number table method: control group (group WT+ C) and ALI group (group WT+ ALI). The KO mice were divided into 3 groups ( n=5 each) using a random number table method: control group (group KO+ C), ALI group (group KO+ ALI) and ALI plus NAD + precursor substances nicotinamide mononucleotide (NMN) group (KO+ LPS+ NMN group). ALI was produced with lipopolysaccharide (LPS) 15 mg/kg injected intravenously.NMN 500 mg/kg was intraperitoneally injected at 1 h before injection of LPS in KO+ ALI+ NMN group, while the equal volume of normal saline was given instead in control group.Blood samples were collected from the abdominal aorta at 12 h after LPS or normal saline injection for blood gas analysis, and the animals were then sacrificed and the lung tissues were removed for microscopic examination of pathologic changes which were scored and for determination of wet/dry weight ratio (W/D ratio), and interleukin-6 (IL-6), IL-1β and tumor necrosis factor-alpha (TNF-α) contents (by enzyme-linked immunosorbent assay)and content of NAD + (using a spectrophotometer) and levels of SIRT1, acetylated nuclear factor kappaB (Ac-NF-κB), acetylated p53 (Ac-p53), acetylated FoxO1 (Ac-FoxO1) and acetylated PGC1α (Ac-PGC1α) (by Western blot). Results:Compared with group C, pH value and PaO 2 were significantly decreased, the PaCO 2, W/D ratio, lung injury score, contents of IL-6, IL-1β, TNF-α and NAD + were increased, expression of SIRT1 was up-regulated, and expression of Ac-NF-κB, Ac-p53, Ac-FoxO1 and Ac-PGC1α was down-regulated in group ALI ( P<0.05). Compared with group WT+ ALI, pH value and PaO 2 were significantly decreased, the PaCO 2, W/D ratio, lung injury score, contents of IL-6, IL-1β and TNF-α were increased, NAD + content was decreased, expression of SIRT1 was down-regulated, and expression of Ac-NF-κB, Ac-p53, Ac-FoxO1 and Ac-PGC1α was up-regulated in group KO+ ALI ( P<0.05). Compared with group KO+ ALI, pH value and PaO 2 were significantly increased, the PaCO 2, W/D ratio, lung injury score, contents of IL-6, IL-1β and TNF-α were decreased, NAD + content was increased, expression of SIRT1 was up-regulated, and expression of Ac-NF-κB, Ac-p53, Ac-FoxO1 and Ac-PGC1α was down-regulated in group KO+ ALI+ NMN ( P<0.05). Conclusion:The enhanced NAD + -mediated deacetylation activity of SIRT1 is involved in the endogenous protective mechanism in mice with endotoxin-induced ALI.