Studies On Protective Effects And Their Mechanisms Of Dark Tea Extracts On Radiation Injuries And Sepsis

Dark tea is one of six tea,belongs to post-fermented tea.In recent years,with the deep research of dark tea,found that dark tea had many active ingredients:such as tea polysaccharide,tea polyphenols,Theabrownin and alkaloids.It is reported that the pharmacological effects of dark tea are anti-obesity,hypolipidemic,lowering cholesterol,anti-oxidation,antibacterial,anti-tumor and so on,which are shown by pharmacology and molecular biology experiments,while it is rarely reported that dark tea possessed radiation protection effects and the treatment of sepsis.In this study,experiments are divided into three parts to study the protective effect of dark tea on radiation damage and sepsis.The chapter 1 is the initial extraction and separation of the active ingredients of dark tea.Hunan Anhua dark tea extraction is extracted in 80? hot water,after that in a variety of organic solvent to obtain dark tea water extracts,polysaccharide and so on.The chapter 2 is about the radiation protection effects of dark tea extracts.Animal experiments and cell experiments were used to investigate the radiation protection effects of dark tea extracts and its mechanism.Animal experiments:30-days survival experiment,Blood and immunological experiments and anti-oxidation experiments are used to study the radiation protection of dark tea extracts.Cell experiments:Toll-like 5 receptors(TLR5)of HEK-BlueTM TLR5 cells were activited by different concentrations of dark tea extracts to observe the mechanism of radiation protection,which is to further study the mechanism of radiation protection.The chapter 3 is about the dark tea extracts on the treatment of sepsis.Animal experiments:sepsis model of mice were established by intraperitoneal injection of 40mg/kg of lipopolysaccharide(LPS)and cecal ligation plus puncture,which were used to observe the 7d survival of sepsis mice were treated with dark tea extracts.Cell experiments were carried out to study the effect of dark tea extracts on the necroptosis of Macrophages induced by lO?g/ml LPS,which is to further study the mechanism of the treatment on sepsis.The results of pharmacological experiments showed that the dark tea water extracts could improve the average survival time and 30d survival rate of ICR mice irradiated with lethal dose significantly.Dark tea water extracts can increase the number of white blood cells,bone narrow nucleated cells,bone marrow DNA content and colong forming unit of spleen in irradiated mice.The activity of SOD,CAT and GSH-Px in liver tissue and lung tissue of irradiated mice increase and the content of MDA decrease,and the water extracts of dark tea showed better antioxidant activity.Cell experiments show that tea polysaccharide can activate TLR5 receptors,which may be one of the Mechanisms of dark tea on radiation protection.Additionally,dark tea water extract can improve the average survival time and 7d survival rate of sepsis mice induced by 40mg/kg LPS and CLP,which maybe related to tea polysaccharide inhibit the necroptosis of Macrophages induced by LPS(10?g/ml).In conclusion,dark tea extracts have a certain degree of radiation protection,its mechanism may be related to its antioxidant activity and activating TLR5 receptors.Dark tea extracts has a certain therapeutic effect on sepsis mice model induced by 40mg/kg LPS and CLP,which may be concerned with inhibition of macrophage necroptosis induced by LPS(10?g/ml).Their mechanism need to be further study.