Pudilan xiaoyan oral liquid alleviates LPS-induced respiratory injury through decreasing nitroxidative stress and blocking TLR4 activation along with NF-ΚB phosphorylation in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Pudilan xiaoyan oral liquid (PDL), collected in Chinese Pharmacopoeia, has been used clinically for treating inflammatory diseases such as upper respiratory tract infection diseases. However, its potential anti-inflammation and the mechanism are still unclear.
MATERIALS AND METHODS: lipopolysaccharide (LPS) was used to induce respiratory inflammation of mice by intratracheal administration. UPLC/MS was performed for components analysis of PDL. Enzyme-linked immune sorbent assay (ELISA) was conducted for determining interleukin-6(IL-6), interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) in serum and supernatant of tracheal tissue while Nitric oxide assay kit for nitric oxide (NO) content. Hematoxylin-Eosin (HE) staining was applied to evaluate pathological lesions. Western blotting analysis (WB) and Immunohistochemistry(IHC) were employed for the determination of Toll-like receptors 4(TLR4), TNF-α, IL-6, inducible nitric oxide synthase(iNOS) and nuclear factor-kappa B p65 (NF-κB p65) protein expressions.
RESULTS: Seven major compounds of PDL were analyzed simultaneously. The treatment of PDL could attenuate LPS-induced histopathological damage of tracheal tissues, followed by reducing pro-inflammation mediators including TNF-α and IL-6 in serum and supernatant of tracheal tissue. LPS-induced nitroxidative stress including NO content and iNOS expression was inhibited significantly by PDL. Furthermore, PDL also down-regulated NF-kB p65 phosphorylation and TLR4 expressions.
CONCLUSION: The results indicated that the PDL had a protective effect on LPS-induced respiratory inflammation injury in mice. Our findings for the first time provide experimental evidence for the application of PDL on respiratory inflammation injury in clinical practice.