Study On The Protective Effect Of Taurine On LPS-induced Acute Lung Injury

Objective: With the gradual development of large-scale and intensive livestock and poultry production in recent years,the incidence of respiratory diseases in livestock and poultry has also increased significantly.The respiratory diseases are mostly caused by severe infections.When the body is subjected to infectious stimuli,various inflammatory response mediators can be produced through the immune response to facilitate inflammatory response and wound repair,but the body's defense function is too strong to trigger a chain explosive tissue cell damage response.The above process occurs in the lungs and can cause acute lung injury(ALI).Most of the traditional treatment programs use antibiotics,but due to the problems of drug resistance and drug residue caused by antibiotic abuse,the effect is usually not ideal or the prognosis is poor.Therefore,relevant workers have put forward the concept of prevention more than cure.Nowadays,not all diseases can be prevented by vaccines.Therefore,it is the important task of relevant workers to find safe,non-toxic and side effects nutritional and immune additives.Studies have shown that taurine can regulate immunity,relieve acute and chronic inflammation caused by various reasons,and maintain cell homeostasis.This study uses preventive addition of taurine in drinking water and induces acute lung injury through LPS to explore the preventive effect and mechanism of taurine on LPS-induced acute lung injury,in order to use taurine as a nutritional immune additive to regulate inflammation the reaction provides a theoretical basis for the purpose of disease prevention and resistance.Methods: Forty male SD rats aged 6-7 weeks were selected as the research objects.Each group was randomly divided into 10 rats,divided into blank control group(C group),taurine control group(T group),and ALI model group(LPS group),taurine prevention group(LPST group).The normal drinking water of C group and LPS group,and 2% taurine were added to the drinking water of T group and LPST group.On the 28 th day of the test,LPS(5 mg/kg)was injected intraperitoneally in the LPS group and the LPST group,and the same volume of normal saline was injected intraperitoneally in the C and T groups.Samples were taken 3 hours after the injection,and serum,peripheral blood,lung tissue and alveolar lavage were collected Liquid to be tested.The thermal drying method is used to measure the lung wet-to-dry ratio(W/D);The automatic blood cell analyzer counts the total number of white blood cells and the proportion of related inflammatory cells in the peripheral blood;The white blood cell counting board combined with Swiss-Giemsa staining is used to determine the total number of white blood cells and related inflammation Count the proportion of cells in BALF,use BCA reagent to determine the protein concentration in BALF;Use ELISA to detect pro-inflammatory factors(IL-1?,IL-6,IL-18,TNF-?)and inhibitors in serum and lung tissue the content of inflammatory factors(IL-4,IL-10),the pathological changes of lung tissue were observed by HE staining;The myeloperoxidase(MPO)activity in lung tissue was detected by colorimetric method;Western-blot method was used(WB)and immu n-ohistochemistry(IHC)to detect the protein expression of TLR4,My D88,NF-?B p65,NF-?B P-p65,MCP-1,CD68 in lung tissue.Results: The results showed that the W/D value of lung tissue in the LPS group was significantly higher than that in the C group(P < 0.05),and the W/D value of lung tissue in the LPST group was significantly lower than that of the LPS group(P < 0.05);Serum and lung in the LPS group the levels of pro-inflammatory factors(IL-6,IL-18,IL-1?,TNF-?)in tissues were higher than those in group C to varying degrees,and those in LPST group were lower than those in LPS group to varying degrees;Anti-inflammatory factors in serum and lung tissue of LPST group the levels of IL-4 and IL-10 were higher than those in the LPS group to varying degrees;Compared with C group,LPS group lung tissue MPO activity was significantly increased(P < 0.01),compared with LPS group,LPST group was significantly reduced(P < 0.01);LPS group lung tissue TLR4,My D88,NF-?B p65,NF-?B P-p65,CD68,and MCP-1 protein expression levels were significantly higher than that of C group(P < 0.01),and LPST group was lower than LPS group to varying degrees;The above test indicators,except for anti-inflammatory factors and taurine levels,were among the C and T groups there was no significant difference between them(P > 0.05).In summary,taurine inhibits the occurrence of ALI by inhibiting the production of a variety of inflammatory cells in the lung,regulating the levels of inflammatory cytokines,and inhibiting the occurrence of ALI,and the inhibition of ALI by taurine may be related to the inhibition of TLR4/NF-?B signaling pathway activation related.