Jiao Mei Gu (JMG) is a type of Dong plant widely growing in Dong autonomous counties, Hunan province, China. As a type of traditional herbal medicine, JMG has been used to treat inflammatory-related diseases such as arthritis because of its prominent anti-inflammatory effects in Dong medicine.
This work investigated the anti-inflammatory effects and mechanisms of JMG on lipopolysaccharide (LPS)-induced inflammatory models.
Endotoxemia was induced in C57BL/6 mice by intraperitoneal injection of LPS (20 mg/kg) and the survival curve of mice treated with safe concentrations of JMG was determined. Serum inflammatory cytokines were detected by the Bio-Plex Mouse Cytokine 23-Plex Panel Kit and enzyme-linked immunosorbent assay (ELISA) at 6 h after drug treatment. Hematoxylin-eosin (HE) staining of important organs was completed at 24 h after treatment. Macrophage inflammation was then induced using 10 μg/mL LPS. The anti-inflammatory effect of JMG was investigated by the quantitative polymerase chain reaction (qPCR) and ELISA. The anti-inflammatory mechanism was determined using western blotting, the electrophoretic mobility shift assay, and immunocytochemistry. Finally, the antimicrobial activity of JMG was verified by survival experiments in vivo and by bacterial culture experiments in vitro.
A 200 mg/kg water extract of JMG was safe for mice. The water extract of JMG had a significant protective effect on LPS-induced sepsis. The MIP-1α (CCL-3), MIP-1β (CCL-4), IL-1β, and TNFα cytokines were significantly decreased at 6 h in the JMG group, when compared with the LPS group. Organ damage was also significantly reduced at 24 h in the JMG group, when compared with the LPS group. In a similar manner, both mRNA and protein levels of the MIP-1α (CCL-3), MIP-1β (CCL-4), IL-1β, and TNFα cytokines were significantly decreased in LPS-induced inflammatory macrophages when treated with JMG. JMG treatment inhibited the phosphorylation of NF-κB p65 and reduced nuclear transduction, thus reducing transcriptional activity. At the same time, we showed that JMG had no protective effect on Escherichia coli-induced sepsis, as well as no antimicrobial activity.
Our results showed that a water-soluble extract of JMG inhibited LPS-induced inflammation via attenuating the NF-κB signaling pathway, which provides an important rationale for the treatment of inflammation-related diseases.
Copyright © 2020. Published by Elsevier B.V.