Study On The Effect And Mechanism Of Tea Polyphenols On Alleviating Heat Stress Damage In Poultry

Heat stress(HS)is one of the important problems restricting the healthy development of the poultry breeding industry.It damages the tissues and organs of the poultry,and severe cases can cause sudden death of the poultry.Tea polyphenols(TP)is a good feed additive with antioxidant,anti-cancer,bacteriostatic,anti-inflammatory and other biological effects,but the protective effect of TP on cardiac muscle cells under heat stress and its protective mechanism No clear statement yet.In this study,a 300-day-old Hyland brown hen and H9C2 cardiomyocytes were used to construct an experimental model of heat stress,and the protective effect of TP on cardiomyocytes under heat stress was explored.Based on the network pharmacological enrichment target of TP for further discussion The TP protection mechanism provides a reference for clinical screening of drugs against heat stress injury.In this experiment,80 Hyland brown hens were randomly divided into 8 groups of 10 chickens.The environment was adjusted for one week,and then the drug was administered for one week.The administration group was drank with 0.2 g/L TP,and was free to drink.The other groups were free to drink water.Finally,all chickens were heat-treated at 0 d,0.5 d,2 d,and 5 d.During the heat stress period,the administration group continued to be drank with 0.2g/L TP,and eggs were collected daily.The chickens were sacrificed at the time point corresponding to the heat stress,and serum and tissue samples required for the experiment were collected;10 mg/L TP were applied to H9C2 cardiomyocytes,and the cells were subjected to 42°C ± 1°C for 0 h,2 h,3 h,5 h Heat stress treatment,and cell samples were collected.Through eggs quality tested,we found that 0.2 g/L TP can suppress the decrease in eggs quality caused by heat stress;Pathological examination of myocardial cells in laying hens showed that compared with the corresponding heat-stressed group,there was no obvious myocardial pathological phenomenon in the test chickens drunk 0.2 g / L TP;detection of LDH,CK,CK-MB and TNF-? in serum,the results found that TP reduced the damage indicators LDH,CK,CK-MB and TNF-? in serum,detection of Caspase 3 protein,TP inhibition Caspase 3 protein was up-regulated under heat stress.The above results indicated that TP can relieve heat stress injury.In order to determine the protective mechanism of TP against slow thermal stress injury,we selected cardiomyocytes as the main research object,and tested the oxidative damage indicator MDA in serum and the antioxidant capacity indicators SOD,GSH-PX,total antioxidant capacity T-AOC and Nrf2,which were important factors in the anti-oxidation of laying cardiomyocytes,showed that TP can increase the content of T-AOC and GSH-PX in serum under heat stress conditions,and has no effect on SOD Significantly reduced MDA content and increased Nrf2 protein levels in laying cardiomyocytes.T-AOC and SOD were up-regulated in H9C2 cardiomyocytes under the action of TP,and HO-1 transcription levels were up-regulated.TP relieved myocardial cells from antipyretic stress injury by enhancing antioxidant capacity;Through the detection of Hsps in cardiomyocytes and H9C2 cardiomyocytes,explored the mechanism of TP-activated heat shock response to relieve heat stress injury of cardiomyocytes,and the results showed that TP can increase CRYAB,Hsp27,and Hsp70 proteins at different time points of heat stress level,TP can alleviate the damage of heat stress to cardiac muscle cells by activating heat shock response.In summary,TP can effectively alleviate the damage of heat stress to cardiomyocytes,and has a good protective effect on cardiomyocytes under heat stress.It can relieve heat stress on the myocardium by enhancing the antioxidant capacity and activating the heat shock response,cell damage,resistance to heat stress on poultry.This study provided a theoretical basis for the development of TP-related drugs to relieve heat stress in poultry.