ABSTRACT
1. Mycoplasma gallisepticum (MG) causes severe lung inflammation and cell damage by activating toll-like receptor (TLR) signalling, the nuclear factor-kappaB (NF-κB) pathway and pro-inflammatory cytokine gene expression. Baicalin (BA) is a flavonoid extracted from Scutellaria baicalensis, which possesses anti-inflammatory and anti-bacterial properties. This study investigated the effect of BA in MG-induced lung inflammation and its potential mechanism in MG-infected chicken embryo lungs and DF-1 cells.
2. The histopathological examination result showed that BA treatment alleviated MG-induced lung pathological changes. In addition, CCK-8 and cell cycle assays showed that BA treatment inhibited MG-induced cell proliferation and cell cycle progression in DF-1 cells.
3. The ELISA and RT-qPCR results demonstrated that BA treatment decreased the expression of interleukin-1beta (IL-1β), IL-6, and tumour necrosis factor-alpha (TNF-α) both in MG-infected chicken embryo lungs and DF-1 cells.
4. The results revealed that BA inhibited mRNA expression levels of toll-like receptor-6 (TLR6), myeloid differentiation primary response gene-88 (MyD88) and nuclear factor-κB (NF-κB), and the nuclear translocation of NF-κB-p65
5. In conclusion, the results showed that BA has a protective effect against MG-induced lung inflammation in chicken by inhibiting the TLR6-mediated NF-κB signalling.
Acknowledgments
The authors are thankful to Yanzhang Gong, Yanping Feng, Shijun Li, Zheya Sheng, and Jinqiu Li for their assistance in this work.
Author contribution
Conception and design of the work: M. Y. Zou, L.Y. Yang, Y. F. Sun; acquisition of data: M.Y. Zou, L.M. Niu, Y. L. Fu; analysis and interpretation of the data: L. M. Niu, Y. B. Zhao; statistical analysis: M. Y. Zou, L. Y. Yang; drafting the manuscript: X. L. Peng, M. Y. Zou; critical revision of the manuscript: Y. B. Zhao, Y. F. Sun, X. L. Peng. All of the authors read and approved the final manuscript for publication.
Disclosure statement
The authors declare no conflict of interest.
Ethical statement
The authors affirm that all of the animal experiments were conducted in accordance with the National Institutes of Health guide for the care and use of Laboratory animals (NIH Publications No. 8023, revised 1978).