关键词: 中药复方呼宁散, 鸡肺源大肠杆菌, 抑菌活性, 抗炎, 抗氧化

Abstract:

This study aimed to investigate the bacteriostatic activity of Huning Powder against E. coli of chicken lung origin, as well as the anti-inflammatory and anti-oxidation effects on lipopolysaccharide (LPS)-induced damage model of chicken embryonic fibroblasts (DF-1). Huning Powder was prepared with 10 Chinese herbs including Morus alba L, Scutellaria baicalensis Georgi, and Taraxacum. The antibacterial activity of Huning Powder against chicken lung-derived E. coli was determined by Oxford Cup method, the minimal inhibitory concentration (MIC) and bactericidal concentration (MBC) of Huning Powder was determined by TTC method, and the bacterial growth curve was drawn. The contents of alkaline phosphatase (AKP), nucleic acid and soluble protein in bacterial culture medium were detected. The LPS-induced DF-1 cell damage model was established and drug was administered after the toxicity of LPS and Huning Powder to DF-1 cells was detected by CCK-8 method. The levels of the inflammatory factors IL-1β, IL-6 and IL-8 were determined by ELISA.The expression of key proteins of Toll-like receptor 4 (TLR4) and nuclear factor kappa B p65 (NF-κB p65) in the TLR4/NF-κB signaling pathway were determined by Western blot. The intracellular levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and reduced glutathione (GSH) were determined by kits. The expression of key proteins of nuclear factor E2-related factor 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) in the Keap1/Nrf2 signaling pathway were determined by Western blot. Results were as follows: Chicken lung-derived E. coli was moderately susceptible to Huning Powder, and the MIC was 250 mg·mL^-1 and MBC was 500 mg·mL^-1. The growth of E. coli of chicken lung origin was inhibited and AKP, soluble protein and nucleic acid content in bacterial cultures were increased by Huning Powder. In cellular assays, the levels of inflammatory factors IL-1β, IL-6, and IL-8 in the supernatant of LPS-induced DF-1 cells were reduced by Huning Powder. The overexpressions of TLR4 and NF-κB p65 proteins were inhibited by Huning Powder. The levels of ROS and MDA were reduced, SOD activity and GSH content were increased by Huning Powder. The expression of Nrf2, NQO1 and HO-1 proteins were increased and the overexpression of Keap1 protein was inhibited by Huning Powder. The traditional Chinese medicine compound Huning Powder had good bacteriostatic activity against chicken lung-derived E. coli and could exert anti-inflammatory and antioxidant effects by regulating the expression of key proteins of the TLR4/NF-κB and Keap1/Nrf2 signaling pathways in LPS-induced DF-1 cells.

Key words: Traditional Chinese medicine compound Huning Powder, chicken lung-derived E. coli, antibacterial activity, anti-inflammation, anti-oxidation