[Dehydroandrographolide succinate inhibits oxidative stress in mice with lipopolysaccharide-induced acute lung injury by inactivating iNOS]

Objective: To investigate the effect of dehydroandrographolide succinate (DAS) on oxidative stress and induced nitric oxide synthase (iNOS) expression in a mouse model of lipopolysaccharide (LPS)-induced acute lung injury.

Methods: Thirty male BALB/C mice were randomly divided into control group, LPS+DAS group and LPS group (n=10). The levels of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), malondialdehyde (MDA) and superoxide dismutase (SOD) in the bronchoalveolar lavage fluid (BALF) were measured. The wet-to-dry ratio (W/D) of the lung tissue was determined to evaluate lung edema. HE staining was used to observe the pathological changes and lung injury scores. The expressions of iNOS mRNA and protein in the lungs were analyzed using RT-PCR and Western blotting, respectively.

Results: IL-1β, IL-6, TNF-α and MDA levels in the BALF, W/D, lung injury scores, and iNOS mRNA and protein expressions increased and SOD in the BALF decreased significantly after intratracheal LPS injection. Compared with those in LPS group, IL-1β, IL-6, TNF-α and MDA in BALF, W/D, lung injury scores and iNOS mRNA and protein expression were significantly reduced and SOD in the BALF significantly increased in LPS+DAS group.

Conclusions: Dehydroandrographolide succinate can alleviate oxidative stress in LPS-induced acute lung injury possibly by inactivating iNOS.