Effects Of TLRs Gene Expression On Peripheral Blood Leukocytes And Breast Tissues By Escherichia Coli (E.coli) Infection In Small Tail Han Sheep

Toll-like receptors(TLRs)are Type I transmembrane proteins that recognize pathogen-associated molecular patterns(PAMPs)and have extracellular domains rich in leucine repeat sequences.It can activate the downstream inflammatory pathway,induce the body's immune system to secrete the corresponding cytokines,so as to clear or resist the corresponding pathogenic microorganisms.The occurrence of mastitis in Small tail han sheep has been a crucial obstacle to the development of sheep industry.Therefore,it has become a very promising research topic of investigating how to use the TLR in natural immune environment to prevent and treat bacterial mastitis.In order to study the expression of TLRs in Escherichia coli(E.Coli)invading the mammary gland of Small tail han sheep,the animals were infected with E.coli(O113),and the mammary gland tissues were detected by q RT-PCR.The relative expression of TLRs in blood and mammary gland tissues was measured at12 h,24,36 h,48h and 72 h after treatment,and the relative expression of TLRs protein in different time period after infection with E.coli was studied by Western-blot(WB).The results showed that TLR1 ~ 10 was expressed in peripheral blood leukocytes of small tail Han sheep after E.coli invading,except TLR8.The TLR2,3,4,5 m RNA in peripheral blood leukocytes of small tail Han sheep after 24 hours of E.coli infection were significantly or extremely significantly increased.TLR2,3,4,5,6,7m RNA were significantly or extremely significantly increased after 36 hours of infection;After 48 h,TLR2,4,5 m RNA were significantly or extremely significantly increased.The relative expression of TLR1,TLR2,TLR4,TLR5,TLR6,TLR7,TLR10 in the mammary gland of the small-tail han sheep was increased after infection with E.coli.Among them,TLR1,4,6 showed a significant increase at 12 h.At 24 h,TLR2,4 was significantly or extremely significantly increased;36h,TLR1,2,4 significant or extremely significantly increased.48 h,TLR1,2,4,6 showed significant or extremely significant increase.72 h,TLR2,4,7,10 were significantly or extremely significantly increased.Compared with the control group,the expression of TLRs protein in the treatment group was up-regulated with the prolongation of infection time,andsignificantly or extremely significantly increased at the 36 h time point after infection.The results indicate that the TLRs could significantly increase the relative expression of TLRs in peripheral blood leukocytes and breast tissues of E.coli,and that the TLRs of the small-tail sheep are involved in the identification of pathogens.This study provides empirical data and preliminary literature for the further research into the mechanism of different TLRs in the pathogenesis of inflammation.