Study On The Distribution Rule Of Tlr4in Chicken Small Intestine

The gastrointestinal tract is not only the main organs of the digestive system, but also is an immune organ, playing an important role in resisting pathogenic microorganism. The innate immunity is the first line of resistance to pathogen in the physical condition. Following the invadating of pathogenic microorganism, the host initiate the innate immune reaction through recognizing PAMs by PPSs, then bring the defense into play. Toll like receptors (TLRs) are one kind of pattern recognize receptors, constituting of extracellular region, transmembrane domain and cytoplasm area, TLR4(Toll-like receptor4, TLR4) is the first TLR related protein founded by people, distributed in most cell lines.The distribution and development role of TLR4in chicken small intestine and the relationship between TLR4and mucosal immunity of chicken was rarely researched. Thus, in this study the changing role of TLR4and neuro-immune-endocrine network and the effect of LPS injecting in the intestinal of KeBao chicken from week1to week6was studied to investigate the interaction mechanisms between intestinal mucosal immunity and TLR4. The main research was as follows:1The age-related changes of TLR4in the intestine of the chickenIn order to study the changes of TLR4in the small intestine of chicken at different ages and discuss the probable interaction mechanism of intestinal mocusal immunity, the distribution and expression changes of TLR4in the chicken intestine was studied by the method of SABC. Result: TLR4was found to be distributed in all ages of the intestine and the density of the TLR4increased steadily following the ages. At the same ages, the distribution of TLR4in the duodenum is the strongest, then jejunum, and ileum least. TLR4was mainly distributed in the intestine epithelial and lamina propria of the intestinal mucosa, most TLR4postive cells wew distributed around the intestinal gland. Some of the immune positive cells were scattered, little were gathered. The shape of the cells was various. The research results show that the development of intestine mucosal is gradually, and immune lamina propria of the intestinal mucosa is the major place for the intestinal immune function, TLR4increased following the ages maybe relative to the defensive reaction against microbial infection of the organism.2The effect of LPS on the expression of TLR4in chicken small intestineThe study was performed to investigate the role of TRL4in the mucosal immune mechanisms through observing the distribution of TLR4in the small intestine, and the bacterial infection model was simulated by injecting LPS. The results were as follows: TLR4express stronger in the LPS treated group compared with the saline injection group in the small intestine, but the laws of the distribution in the two groups was substantially the same, TLR4was mainly distributed in the mucosal lamina propria,most was observed in the lamina propria closing to the epithelial and around the intestinal glands. The study also discovered that a strong positive signal expression of TLR4was occurred in the intestinal epithelium, and it was further validated that the intestinal epithelium, mucosal lamina propria and intestinal glands were the main places of the intestinal mucosal immune. In addition, the study also confirmed that TLR4was relatived to the immune responses in order to maintain the normal physiological functions of intestinal tract when the exogenous pathogenic microorganisms was invaded.3.The distribution of argyrophilic cells in small intestineThe method of this study adopt silver staning to survey the distribution and variation of argyrophilic cells in small intestine to explore the relationship between neuroendocrine and immune.The result shows that:argyrophilic cells express at ages in chicken.What’s more,it shows the regular pattern of increasing in wave mode as age increases,that is: there is a continuously increasing of argyrophilic cells in small intestine in chicken at1-3weeks of age and decreasing at4、5weeks of age and then significantly increase at6week. Argyrophilic cells mainly distribute in the intestinal lamina propria,most scattered,some of them are relatively centralized.The argyrophilic cells are various in shape,most of the spindle-shaped argyrophilic cells distribute in lamina propria closed to the epithelial,while the round and irregular-shaped mainly gather in central lamina propria and lamina propria around the intestinal glands.The distribution and shape of most argyrophilic cells are consistent with the experiment of TLR4.This results indicate that the argyrophilic cells play an quite important role in intestinal tract similar with immunocytes in the organism.Its functional mechanism may modulated by the nervous-immune-endocrine net and expression of TLR4.4.The effect of LPS on the expression of argyrophilic cell in chicken small intestineTo explore the relationship between the argyrophilic cells and mucosal immune,this experiment came to observe the variation of argyrophilic cells in small intestine of chicken after injecting LPS to explore the relationship further.The results of the experiments suggests that there are more argyrophilic cells in the LPS group compared with the Normal Saline group significantly.They mainly distribute in the Inherent layers of bowel mucosa.Except increasing of the quantity,there are also differences in shape and distribution,such as spindle cells are increasing and some particulate matters in the cell cytoplasm entended enteric cavity and also argyrophilic cells aggregate in the lamina propria in jejunum and ileum.This series changes indicate that argyrophilic cells play an important role in intestinal mucosa.The increased expression of TLR4and argyrophilic cells stimulating by LPS shows that the mechanism of argyrophilic cells mediating mocosal immuine in intestinal canal may tightly related to TLR4.