Experimental Study On The Expression Of TNF-α And IL-6 In The Different Rat Models With Infection Pre-and Post-splenectomy

Objective: To observe the change of cytokines in the different rat models with splenectomy and infection in different times.Methods: Three animal models of control, liver cirrhosis and immunosuppression were established in 180 Sprague-Dawley rats, half of them were performed splenectomy, each rat was carried out caecal ligation and puncture (CLP), measured TNF-α and IL-6 levels in serum with ELISA. Moreover, pathological studies were performed. The expression of the cytokines gene in the spleen of liver cirrhosis group was analyzed semiquantitatively at different times with reverse-transcription polymerase chain reaction (RT-PCR).Results: 1. TNF-a level in splenectmized groups reached their maximum at the 3rd hour (p<0.01) after CLP and decreased smoothly after 6th hour. The TNF-α level of control group was much higher than that of other tow groups at the 3rd hour (p<0.01). TNF-a in liver cirrhosis group exceeded that of control group at the 6th hour after CLP. TNF-α in immunosuppression group was always lower than that of control group (p<0.01). The change of TNF-α in spleen groups were resemble to those in splenectmized groups, but TNF-a in spleen control group was always lower than that in splenectmized control group(p<0.05?.01). 2. IL-6 levels increased obviously in splenectmized groups after CLP with a peak response at the 6th hour, and then decreasedsteadily. IL-6 levels in spleen control group and spleen liver cirrhosis group were continuously increased. Among them, IL-6 levels in spleen control group increased most and was higher than that in splenectmized control group (p<0.01). 3. Expression of TNF- α mRNA in liver cirrhosis group reached their maximum at the 3rd hour (P<0.01) after CLP and decreased smoothly after 6th hour. Whereas, expression of IL-6 mRNA in liver cirrhosis group increased smoothly reached their maximum at the 12rd hour (p<0.01) after CLP and decreased after 24th hour. 4. The rats in all groups had different degree of perennial infection and pathological changes of their important organs, the rats in immunosuppression group had the most changes and the rats in liver cirrhosis group were second to it.Conclusions: 1. TNF-α was one of the most important cytokines leading to MODS and IL-6 might take a protecting role in this process. 2. In normal condition, the effect of IL-6 was related to spleen, but in pathogenic condition, no matter performing splenectomy or not, the protect effect of IL-6 was all decrease in different degree. 3. The abilities to clearing toxins of rats in liver cirrhosis and immunosuppression groups during intra-abdomen infection were reduced and they were easier to cause MODS may well be related to them. 4. In liver cirrhosis group, pathologic spleen still have partial function of regulation for the cytokines expression, although with immunological damage.