The Significance Of Interleukin17(IL-17) In Neonatal Rats Septicemia With E.Coli

Objective:Neonatal sepsis is one of clinical infection, high susceptibility, and mortality rate is also high. Most studies suggest that the release of a large number of inflammation mediators leading to acute inflammatory response syndrome is an important pathogenic mechanism of sepsis. Innate immunity is considered to be a natural immune defense, which is the body formed gradually in the long-term phylogenetic and evolutionary process. Mononuclear-macrophages, NK cells, γδT cells, NKT cells are the main components of natural immune system, they are able to phagocytic destruction, elimination and release of various cytokines and inflammatory mediators, identifying and presenting antigens to start the specific immune response, the role of innate immune cells in the inflammatory response is extremely important impact on the outcome and prognosis of the disease. N K cells,78T cells, NKT cells can secrete the cytokine of IL-17. IL-17can be induced in defense of IL-6、IL-1β、TNF alpha in infective inflammation,which can play an importment role of promoting inflammation factors and inflammation.The existence of molecular specificity of the hemoglobin scavenger receptor (CD163)of the surface of monocytes-macrophages can refer and guide endocytosis of LPS and anti-inflammatory cytokine production, and its also off to the blood circulation, the plasma of CD163play anti-inflammatory and immunomodulatory role. Previous studies in this group was confirmed in Escherichia coli infection of neonatal rat sepsis model, CD163in monocyte-macrophage cell surface and plasma have anti-inflammatory role in sepsis,which can take the development of great significance.Thus,we establish neonatal rats with Escherichia coli sepsis model to analysis of the cytokine IL-17expression in the lung, liver tissue and plasma levels of change, and to investigate the IL-17in neonatal rat sepsis in the mechanism of action,throngh that we also can learn more about the surface of lymphocytes secrete cytokines IL-17and macrophage CD163role in the inflammatory response,and we can immune status through changes in their expression levels.Methods:Choosing847-day-old Sprague-Dawley(SD) rats with Special Pathogen Free(SPF), weight from16g to20g, either sex. They were divided into two groups:control group and septicemia group, with42neonatal rats in each group. All the rats were randomly divided into different time points of the two groups,including2,4,6,8,12,24,48hours.And there were6neonatal rats in each time point. We established the sepsis model with the method of intraperitoneal injection of E.coli.And the control group rats were injected with the same amount of normal saline. At each target time point,we got the blood from heart after anesthetizing animals,and the lungs and livers were fixed in formalin for analysis. Immunohistochemistry was chosen to analyze the expression of IL-17in the lungs and livers. ELISA assay was used to detect the levels of IL-17in plasma.Results:1.The plasma IL-17and lung tissue, liver tissue at all time points of IL-17expression level had no significant difference in the control group of neonatal rats (P>0.05);2. The plasma of IL-17the expression level, with the extension of the experimental time and gradually increased to about12hours and reached the peak, has been extended to48hours in the sepsis group of neonatal rats;3.In sepsis group, IL-17expression in the lungs of neonatal rats, as between the experimental extended, and reached a peak about12hours, the experiment to48hours has been at a high level;4. Sepsis group newborn rat liver tissue expression of IL-17, higher levels of IL-17in the experiment to4hours, the liver tissue, then the level is slightly decreased, but the experiment to about12hours to achieve a higher level again, to48hours of the experiment has been maintained at a high level;5. Experimental progress to two hours, IL-17concentration in the sepsis group, plasma and lung tissue.IL-17expression in the liver tissue, respectively, with the control group showed no significant difference (P>0.05); experimental progress to the meter after four hours, the sepsis group, plasma IL-17level and lung tissue, liver tissue IL-17expression higher than those in the control group, there is a significant difference statistical significance (P<0.01).Conclusion:1、with the process of neonatal rats Escherichia coli sepsis, the sepsis group, plasma IL-17levels and lung tissue, liver tissue expression of IL-17there was a significant difference which compared with control group, suggesting that IL-17plays an important role in the development of sepsis.2、the sepsis group of neonatal rats in plasma IL-17levels and lung tissue, liver tissue expression of IL-17was time-dependent increased with the progress of infection, suggesting that the body of pro-inflammatory response intensified.3、 Task Force Previous studies have found that the level of anti-inflammatory effects of CD163was also time-dependent changes in the process of neonatal rats with Escherichia coli sepsis, the study also found that the proinflammatory role of IL-17into a time-dependent changes, suggesting that IL-17and CD163in the dynamic balance of pro-inflammatory response and anti-inflammatory response may limit the inflammatory reaction process and prognosis.4、Thus, IL-17and CD163can be used as a new marker for the assessment of sepsis progression, and then to carry out the immune regulatory intervention in neonatal severe infection,and which can provide further theoretical basis.