Establishment Of LPS-induced Chick Inflammation Model And Its Application

Objective:LPS,as one of the important pathogenic factors of G-bacteria,can causes animal diseases,which can lead to endotoxemia and deaths because of acute lung injury and liver and kidney dysfunction.However,the researchs in poultry have been rarely reported and mainly focused on causing changes in body temperature and local tissue lesions and inflammatory factors.There are lesser reports on the inflammation and death of poultry.This is the tolerance of birds to LPS,or not sensitive?This experiment attempts to establish an inflammation model of LPS-induced chicks in order to explore the pathogenicity and inflammatory condition of LPS on chicks.Methods:180 chickens of 1 old meat were divided into blank group?K?,LPS group?L?,hemagglutinin group?N?,hemagglutinin+LPS group?N+L?,15 in each group and 3 repetitions,K group was intraperitoneally injected with sterile saline;N group was given a jugular vein injection of hemagglutinase 250U·kg^-1;L group was intraperitoneally injected with LPS 10 mg·kg^-1;in the N+L group,250 U·kg^-1hemagglutinase was preinjected into the jugular vein for 15 min,and 10mg·kg^-1LPS was intraperitoneally injected;0.2 mL every chick.The clinical symptoms of chicks in each group were observed in real time within 24 h after injection;the rectal temperatures were measured at 0,1,3,6,12,and 24 h,respectively;and after 24 h,blood was collected for white blood cell count and detection of cytokines?TNF-?,IL-1?,IL-6,IL-8,NO?;observation of anatomical pathological changes in chicks after bloodletting of the neck.At the same time,the pathological changes were observed by heart,liver,spleen,lung and kidney tissues,and the inflammation model was comprehensively evaluated.The animal model was treated with the commercially available anti-inflammatory drug dexamethasone,and the therapeutic effects were evaluated from clinical symptoms and tissue lesions.Results:There was no significant change in the status of chicks in K and N groups within 24 h;some chicks in L group had decreased diet and depression in 6 h,and returned to normal after 6 h;the diet in N+L group decreased significantly or even no appetite,depression,piled up and sleepiness within 12 h,and about 20%of the chicks die within 24 h,and the dissection changes mainly include a large amount of red and black interstitial fluid exudated in enterocoelia.The temperature of the chicks in K and N groups were maintained balance within 24 h,and the temperature in L and N+L groups decreased at 1 h after injected,and gradually increased to normal after 3 h.White blood cell count showed that the K group was significantly higher than N,L,N+L groups?P<0.05?.The results of ELISA showed that the levels of TNF-?,IL-6and IL-8 secreted by chicks in N,L and N+L groups were significantly higher than K group?P<0.01?;the levels of IL-1?secreted by chicks in N and N+L groups were significantly higher than in K group?P<0.05,P<0.01?;and the difference between L and K groups was not significant?P>0.05?;the NO content in the L and N+L groups was significantly higher than K group?P<0.01?,but the N group was lower than the K group and there was no significant difference?P>0.05?.The dissection results showed that the liver and some other tissues of the chicks in the N+L group had obvious bleeding,and no abnormalities were observed in other groups.The results of HE staining showed that there were obvious hematocytosis and hemolysis in the heart,liver,spleen,lung,kidney tissues of the chicks in the N+L group,and a small amount of exudate infiltrated in the tissue.The results of the model application showed that there were obvious clinical symptoms in the M group compared with the K group within 24 h after injected.The content of inflammatory factors increased in 72 h,and the bleeding symptoms in the enterocoelia and liver were observed in the dissection,but the Y group improved compared with the M group.Conclusion:Stimulated of chicks with LPS alone failed to establish an ideal model of inflammatory,but with the aid of hemagglutinase,the chicks were stimulated to obtain a reproducible pathological model.The positive drug dexamethasone treatmented model showed improvement in symptoms,suggesting hemagglutinin plays an important role in chick inflammation,but the specific mechanism of action of LPS and hemagglutinin on chicks needs further study and verify.