The Protection Effect Of RhTNFR:FC On Lung In Septic Rats

Objective:To study the influence of rhTNFR:Fc (etanercept) to the changes of the level of serum tumor necrosis factor (TNF-α)、interleukin-1(IL-1)、intercellular adhesion molecule-1(ICAM-1), to the expression of nuclear factor κB (NF-κB) in the lung tissue and lung inflammatory changes of septic rats, to explore whether etanercept has a protective effect to lungs of septic rats.Methods:(1) Clean grade Sprague Dawley (SD) rats108, male or female, were randomly divided into three groups:(1) control group (A group, n=36), sepsis group (group B, n=36), treatment group (C group, n=36);(2) Thirty-six animals in group A did laparotomy flip cecum after anesthesia, then closed abdomen. At the time point of3h,9h,24h,36h,48h and72h after operation, blood samples were obtained from the abdominal aorta, using enzyme-linked immunosorbent assay to detect levels of tumor necrosis factor (TNF-alpha), interleukin-1(IL-1) and intercellular adhesion molecule-1(ICAM-1).Then, open the chest, take a little mung bean size lung tissue to detect protein imprinting experiments(Western blot) of NF-kB protein content.Take a little left upper lung tissue for pathological section, in order to observe the change of inflammation. Each phase point had six rats.(3) Group B animals were carried out the same steps with the control group after cecum ligation perforation (CLP) at each time point of3h,9h,24h,36h,48h and72h after operation.(4) C group of rats were immediately injected etanercept with2mL/kg (1g/L)by tail vein after CLP. Then did the same steps with the sepsis groups at the time point of3h,9h,24h,36h,48h and72h after operation.(5)All of the data was expressed with "mean±standard deviation", and analyzed by SPSS13.0statistical software package. Using Spearman rank correlation analysis to implement correlation analysis.Result 1. The variation of serum TNF-a levels:the level of serum TNF-a in sepsis group and treatment group were the maximum at the time point of3h, then as the time went by, the concentration level about two groups began to decline, but still higher than the control group. Sepsis group and treatment group compared with control group,they had significant difference (P<0.01) at each phase point after CLP. The serum TNF-a levels of Treatment group were lower than those of sepsis group, compared with sepsis group had significant difference (P<0.05) at each phase point after surgery.2. The change of serum IL-1levels:the level of serum IL-1in sepsis group and treatment group were the maximum at the time point of3h, then as the time went by, the concentration level about two groups began to decline, but still higher than the control group. Sepsis group and treatment group compared with control group,they had significant difference (P<0.01) at each phase point after CLP. The serum IL-1levels of Treatment group were lower than those of sepsis group, compared with sepsis group had significant difference (P<0.05) at each phase point after surgery.3. The change of serum ICAM-1levels:the level of serum ICAM-1in sepsis group and treatment group were the maximum at the time point of3h, then as the time went by, the concentration level about two groups began to decline, but still higher than the control group. Sepsis group and treatment group compared with control group,they had significant difference (P<0.01) at each phase point after CLP. The serum ICAM-1levels of Treatment group were lower than those of sepsis group, compared with sepsis group had significant difference (P<0.05) at each phase point after surgery.4. Biopsy results show that the integrity of alveolar tissue in the control groups is good,and surrounding it without obvious inflammatory cell infiltration and tissue edema.We can see in the sepsis group lung tissue,the integrity of alveolar tissue is destructive,around it with obvious tissue edema and inflammatory cell infiltration. Compare with sepsis groups, the treatment groups’ integrity of alveolar tissue structural is better,and lower in the surrounding about tissue edema and inflammatory cell infiltration. But increase compare to the control group. 5.The results of western-blot were shown that the electrophoretic bands area of sepsis group were significantly greater than the treatment group and the control group,the color of it was darker than the other two groups.The treatment group’s electrophoretic bands area and color were lower than the control group at the time point of3h, the rest of time points were higher,but lower compared with the sepsis group.5. The result of correlation analysis among TNF-a, IL-1, and ICAM-1:1). It has a significant positive correlation between TNF-a and ICAM-1, the correlation coefficient was0.415, P>0.05,;2).It has a significant positive correlation between ICAM-1and IL-1, the correlation coefficient was0.983, P<0.01;3).It has a significant positive correlation between TNF-a and IL-1, the correlation coefficient was0.342, P>0.05.Conclusion1.In the septic rat models, the increase of NF-kB protein expression level and the pathological sections results are suggestive of the presence of inflammatory reaction in the lung tissue of septic rats.2.In the model of septic rats, the level of TNF-a, IL-1, ICAM-1and other inflammatory factors abnormally elevated,they are the main factor that caused the systemic inflammatory response and lung inflammatory injury caused by sepsis.3.rhTNFR:Fc (Etanercept) can reduce the release of septic rats serum TNF-a, IL-1,ICAM-1and other inflammatory cytokines, and also the expression of nuclear factor κB (NF-κB) in the lung tissue, it may interfere with the core aspects of inflammatory response in the lungs caused by sepsis, thereby reducing the lung inflammatory injury.4.rhTNFR:Fc(Etanercept) as a TNF-α receptor blocker may partially block early inflammatory response process, reduce the degree of sepsis inflammatory response, which has a protective effect to the inflammatory injury in septic rat lungs.