Abstract: BACKGROUND: Studies have shown that tea polyphenols have anti-inflammatory effects on multiple organs, but there are few studies on the effects of tea polyphenols on central nervous system inflammation caused by exercise fatigue. 
OBJECTIVE: To explore the central anti-inflammatory effect and mechanism of tea polyphenols in exercise fatigue.
METHODS: 7-week-old male Kunming mice were divided into quiet control group, fatigue model group, and tea polyphenols group. In the fatigue model group, mice were given exhaustive swimming at one time. In the tea polyphenols group, tea polyphenols were injected into abdominal cavity half an hour before exhaustive swimming. The exhaustive swimming time in mice of fatigue model group and tea polyphenols group was recorded. Samples were taken from mice in each group after two hours of exhaustive swimming. The changes of brain tissue morphology and structure in each group were observed by hematoxylin-eosin staining. Western blot assay or real-time fluorescence quantitative polymerase chain reaction were used to detect the expression of inflammation-related factors, the activation of microglia, and the activation of STAT3/nuclear factor-κB p65 inflammatory pathway in the brain tissue of mice. Enzyme-linked immunosorbent assay was used to detect the levels of plasma inflammatory factors.
RESULTS AND CONCLUSION: (1) Compared with the fatigue model group, the swimming exhaustion time of mice in the tea polyphenols group was significantly prolonged. (2) No abnormality was found in the hematoxylin-eosin staining results of brain tissues of mice in each group. (3) Compared with the quiet control group, the expression levels of inflammatory factors tumor necrosis factor α protein, interleukin-1β protein, M1 activated microglia marker-inducible nitric oxide synthase protein, nuclear factor-κB p65 protein and mRNA, and p-STAT3 protein and STAT3 mRNA in the fatigue model group were significantly increased, while the expression levels of anti-inflammatory factor interleukin-10 protein and M2 activated microglia marker-arginase 1 protein were significantly decreased. Compared with the fatigue model group, the inflammatory reaction, microglia types and signal molecules showed opposite obvious changes in the tea polyphenols group. (4) The expression levels of tumor necrosis factor α, interleukin 1β, interleukin-10 in peripheral plasma and brain tissue were consistent in mice of each group. (5) To sum up, exercise fatigue can trigger inflammatory reaction of nerve center, and tea polyphenols can alleviate this inflammatory reaction, and then enhance the fatigue resistance time of mice. The effects of exercise-induced fatigue and tea polyphenols on the inflammatory reaction in the brain may be completed through STAT3/nuclear factor-κB p65 pathway. 

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words:  tea polyphenols, exercise-induced fatigue, central inflammation, microglial cell, inflammatory pathway, engineered tissue construction