| Severe trauma can cause not only the lesion of local tissues and malfunction ,but also the systemic inflammatory response. This course is always accompanied with infection. Adequate systemic inflammatory response have important protective effect. Once the inflammtory response is out of control, a lot of severe complications will occur finally. Lipopolysaccharide(LPS)of gram-negative bacteria can activate the inflammatory signal transduction pathway of nuclear factor- κ B(NF- κ B), and lead to the expression of inflammatory cytokines(TNF, IL-1) causing septic shock. So it is important to inhibit the activation of NF- K B and reduce the production of inflammatory cytokines for the treatment of traumatic infection.A kind of new protein molecule, zinc finger protein A20(ZFPA20) has been found in recent years' researchs of cellular endogenous protective mechanism. It is confirmed that zinc finger protein A20 is critical for the regulation of inflammatory responses through terminating the activation of NF- K B induced by LPS or TNF. It is the important regulation protein for inhibiting inflammatory responses in vivo.Therefore, this study was to investigate the expression of zinc finger protein A20 in tissues and macrophages after trauma or with infection and its anti-inflammatory effects. In this experimental study, the expression and characteristics of zinc finger protein A20 in the process of trauma or with infection were systemically observed in mouse model of fracture with RT-PCR, western blot, immunohistochemistry, histopathology, gene transfection, EMSA, ELISA and biochemical analysis of enzyme. Then the expression and characteristics of zinc finger protein A20 in RAW264.7 cells were studied. Zinc finger protein A20 plasmids were transfected into RAW264.7 cell by liposomes, at the same time, we stimulated cells with LPS. The regulation role of A20 on activation of NF- K B and on expression of inflammatory cytokines were systemically studied. We also studied the protective role of zinc finger protein A20 in tissues through injecting the ectogenous A20 full length plasmid via tail vein.The results and conclusions are shown as follows:1. There was low expression of zinc finger protein A20 in simple trauma. The expression of A20 mRNA and protein elevated obviously at 0.5h after injecting with LPS. The expression of A20 mRNA reached a peak during 0.52h, and decreased after 2h.But expression of A20 at each time point were higher in LPS group than that in simple trauma. The expression of A20 elevated obviously at 0.5h after injecting with LPS in trauma plus LPS group, and remained at highest level during 0.5 2h, and was much higher significantly than that in LPS group. The expression of A20 protein elevated obviously at 0.510h after LPS injection. In addition, zinc finger protein A20 was shown to be expressed in other tissues such as lungs spleen kidneys and intestines after trauma and endotoxemia.2. Just like in tissues, the expression of zinc finger protein A20 mRNA in RAW264.7 cell was also shown to be significantly increased immediately after LPS stimulation: The expression of A20 mRNA was lower before stimulation. It elevated at 0.5h after stimulation with LPS, reaching a peak at 1h. It suggests that LPS stimulation could also induce the temporary expression of A20 in macrophages.3. Gene transfection experiments indicated that transfection of full-length A20 gene could significantly inhibit the activation of NF- K B in RAW264.7 macrophages and the production of TNF a , while transfection of A20 N-terminal sequences had no significant effects on NF- K B activation and TNF a production induced by LPS. It suggests that A20 might play an important role in regulation of LPS-inducing inflammation as an endogenous anti-inflammatory protein.4. In vivo transfection of full-length A20 gene could significantly reduce hepatic pathological alterations, plasma levels of ALT and TB and TNF a levels in hepatic tissues in mice subjected to trauma and endotoxemia. In addition, A20...
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