Baicalin ameliorates Mycoplasma gallisepticum-induced lung inflammation in chicken by inhibiting TLR6-mediated NF-κB signalling

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.

KEYWORDS:

• Baicalin
• Mycoplasma gallisepticum
• lung inflammation
• chicken
• gene expression

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).

Additional information

Funding

This work was supported by the National Key Research and Development Program of China [2017YFD0501500] and the National Natural Science Foundation of China [Grant No. 31972681].