Mechanism Of Inhibitory Effects Of A-cyperone, Astragaloside Ⅳ And Andrographolide On The Attaching And Effacing Lesions Of E. Coli To Chicken Type Ⅱ Pneumocytes

chicken type II pneumocytes, the effects of α-cyperone, astragaloside IV andandrographolide on adhesion of chicken pathogenic E. coli O78to chicken type IIpneumocytes was investigated by coating plate count, scanning electron microscope(SEM), TEM, flow cytometry (FCM), LSCM and RT-PCR. The results found thatα-cyperone, astragaloside IV and andrographolide significantly decreased the quantityof chicken pathogenic E. coli O78to chicken type II pneumocytes, decreased theinjury of chicken pathogenic E. coli O78to chicken type II pneumocytes, increasedthe expression of F-actin, and significantly inhibited cytoskeletal rearrangement. Theinhibitory effect on cytoskeletal rearrangement was associated with inhibiting theexpression of Nck-2, CDC42, Rac1gene by α-cyperone, inhibiting the expression ofNck-2, CDC42, Rac1and RhoA gene by astragaloside IV, and inhibiting theexpression of RhoA gene by andrographolide.On the basis of the injury model of chicken pathogenic E. coli O78adhesion tochicken type II pneumocytes, the effects of α-cyperone, astragaloside IV andandrographolide on inflammation of chicken pathogenic E. coli O78to chicken typeII pneumocytes was investigated by ELISA and RT-PCR. The results found α-cyperone, astragaloside IV and andrographolide significantly inhibited the expressionof TNF-α, IL-1β, and promoted the expression of IL-10, IL-4. α-cyperone,astragaloside IV and andrographolide significantly inhibited the expression of TLR-4mRNA, astragaloside IV and andrographolide significantly inhibited the expression ofTLR-5mRNA. α-cyperone and astragaloside IV significantly inhibited the expressionof ERK and P38，andrographolide significantly inhibited the expression of JNK.In summary, α-cyperone, astragaloside IV and andrographolide couldsignificantly inhibit the adhesion of the chicken pathogenic E. coli to chicken type IIpneumocytes, reduce A/E injury including adhesion injury and inflammation injury,induced by chicken pathogenic E. coli. These results will provide a new evidence forXiang-Qi-Tang to prevent chicken colibacillosis.