Expression And Regulation Of The Intestinal AvBD6 And ChTLR15 Influenced On The Chicks Infected With Salmonella Pullorum

Salmonella pullorum is one of the most serious intestinal bacterial, especially the harm to chicks is the most serious. Avian (3-defensin6 (AvBD6)high expression in the gastrointestinal tissue and wide antimicrobial activity. Chicken toll-like receptor15 (ChTLRl5) can identify salmonella,induce the body to autoimmunity,and ChTLR15 was different with any known vertebrate TLR, it should be unique for avian species.This study carried out research of the natural immune regulation mechanism of AvBD6 and ChTLR15 in the process of anti Salmonella pullorum infection. This experiment used Salmonella pullorum to infect the chicks at the age of 14 days, build Salmonella pullorum infection model and observe its pathological changes.The small intestine from the infected chicks were sampled at different time points post infection. Fluorescence real-time quantitative PCR was used to detect the transcription level changes of AvBD6 and ChTLR15 in the small intestine tissue,and in situ hybridization method combined with laser confocal microscope to detect the distribution of AvBD6 and ChTLR15mRNA in the small intestine tissue,details and results are as follows:1.Roman chicks infection with Salmonella pullorum and pathological changesThe experimental group was orally inoculated with 0.5 ml of the bacterial suspension containing 109CFU/ml and the control group was given 0.5 ml of PBS, Chicks pathological changes observed after infection.The results show that Salmonella pullorum can cause Roman chicks spleen, liver, heart and bowel appear obvious pathologic histology changes.Hepatomegaly, necrosis of liver surface with white point,White nodules on the heart,Small intestine and rectum bleeding point.Small intestinal villus were damaged and even fall off,the center axis of the intestinal villi appear more red blood cells, inflammatory cells were increased, columnar epithelial cells are lysed.2.AvBD6 and ChTLR15 mRNA transcription level in the small intestinal tissue of infection chicksRoman chicks inoculated with Salmonella pullorum at the age of 14 days,collec-ted duodenal,Jejunum,ileum tissue after infection within 48h (0h,6h,12h,24h,36h and 48h),using real-time quantitative PCR to detect AvBD6 and ChTLR15genes expression patterns during infection.The results showed that after the chicks infected with Salmonella pullorum the AvBD6 and ChTLR15 were both expressed in each bowel tissues, and the relative expression in the duodenum was the highest The relative expression levels showed a rising trend in the 0h-24h, and decreased in 24h-48h, the level of AvBD6 and ChTLR15 expression in 24h was significantly higher than oh (P<0.01),and the expression of AvBD6 in 24 h was significantly higher than thel2h(P<0.05;.At the same time,the level of AvBD6 and ChTLR15mRNA transcription in the duodenum was significantly higher than in the ileum(P<0.05),compared with the jejunum, the difference was not significant (P> 0.05),and no significant difference in the ileum and jejunum(P> 0.05).But in the same conditions,AvBD6 and ChTLR15mRNA transcription level difference was not significant(P>0.05).3.AvBD6 and ChTLR15 genes in situ expression in the small intestinal tissue of infection chicksAccording to the results of quantitative PCR, collected duodenum, jejunum and ileum tissue infection at 24h,using in situ hybridization technique to detect location of AvBD6 and ChTLR15 gene in intestine in situ of chicks infected with Salmonella pullorum at 24h.The results showed that after chicks infected with Salmonella pullorum, AvBD6 and ChTLR15 mRNA were distributed in the intestinal tissue, which were mainly distributed in the central axis of intestinal villi, fluorescence signal in the duodenum was the strongest.The above experiments show that after chicks infected with Salmonella pullorum, the expression and distribution of AvBD6 and ChTLR15mRNA in chicks intestine has certain regularity. The expression level of AvBD6 and ChTLR15mRNA showed a positive correlation in the duodenum and jejunum. AvBD6 resistance to Salmonella pullorum infection induces expression of TLR15 may be mediated signal transduction.