The Research On The Effects Of TLR2、TLR4and Related Cytokines To Cow Uterus Infected With Staphylococcus Aureus And Escherichia Coli

Endometritis is a common obstetric disease in dairy cows, which leads to fertilization failure, resulting in serious economic losses. The parturient canal remains open in the first several days after parturition, the bacterias invade into the uterine cavity and cause the risk of the occurrence of endometritis. Escherichia coli and Staphylococcus aureus the most common isolates clinically. After invading into the uterine cavity with the pathogenic bacteria, the development of endometritis depends upon bacterial virulence and immune conditions of uterus local and systemic. The uterus local immunity, especially local innate immunity plays a major role in anti-infection. Toll-like receptors and the related cytokines are of the essence in the local innate immunity.Six healthy cows were selected10days after parturition as experimental animals, A suspension of E. coli and Staphylococcus aureus were infused once into uterine horn by operation, body temperature, heart rate and breathing rate were measured preinoculation(Oh) and at3、6、12、24、36、48、72and96h post inoculation; Peripheral blood was collected for blood routine test; Endometrial biopsy samples were collected for cytological examination; Uterus tissue was collected for observing the structure dischanges96h post inoculation, in addition, ultrastructure was observed using scanning electron microscope; Plasma IL-1β、IL-6、 IL-8、SAA and TNF-a concentrations were measured with ELISA; Relative gene expression analyses of TLR2、TLR4、IL-1β、IL-6、IL-8、TNF-α were performed on RNA extracted from peripheral white blood cells and uterine secretion using quantitative real-time PCR. The results were as follows:1. There was no difference in breathing rate between preinoculation and post inoculation; After inoculation,body temperature and heart rate had a rising trend, but there was no significant difference compared with preinoculation;6h,12h post inoculation, the number of neutrophils in the peripheral blood was significantly higher than preinoculation (P<0.05); Cytologic examination of endometrial samples revealed that%PMNs had a long-term increase, and the difference was significantly between preinoculation and post inoculation (P<0.01).2. After inoculation, endometrial epithelial degeneration, necrosis, and a large number of neutrophil infiltrating were observed. The endometrial was severely impaired and lost the original structure, the unimpaired epithelial cells and the complete structure of cilia and microvilli were not observed basically using scanning electron microscope.3The peripheral blood plasma TNF-a concentrations did not change significantly, and IL-1β IL-6、IL-8、SAA concentrations were in the varying degree increases, and the difference was significantly between preinoculation and post inoculation (P<0.05); TLR2and TLR4of Peripheral leukocyte and secretion mRNA expression were significantly higher than preinoculation, Related cytokines IL-1β、IL-6、IL-8and TNF-a mRNA expression also increased together with Toll-like receptors, and the the difference was significant (P<0.05).In conclusions:intrauterine infusion of E. coli and Staphylococcus aureus affected the indexes of blood biochemistry and endometrial biopsy cytology, leading to evident pathological changes on endometrium; intrauterine infusion of E. coli and Staphylococcus aureus in cows resulted in a rapid activation of the local innate immune response, characterized by infiltrating PMNs into the endometrium and up-regulation of gene expression for TLR2, TLR4and the related cytokines.