| Objective: The most common way of treatment of proliferative vitreoretinopathy (PVR) is operation, but the result of operation is not so satisfied .Researches are obligated to investigate the mechanisms of this disease in order to find a safe way to treat PVR.The basic pathological process of PVR involves several stages, including migration and proliferation of retinal pigment epithelial cells(RPE), collegen production, membrane formation and contraction followed by tearing of retina.The end of this process is retinal detachment and blindness. PRE are the major proliferative cells and cytokines play an important role in this process . Nuclear factor- K B (NF- K B) is a protein transcription factor first identified by Sen and Baltimore .Its functions are to enhance the transcription of a variety of genes,including cytokines and growth factors, adhesion molecules,immunoreceptor and acute-phase proteins. In quiescent cells, NF- K B is sequestered in the cytoplasm through its interaction with the inhibitors I K B, it can be activated by a variety of stimuli, including bacterial endotoxin,IL-l,mitogens and certain chemical agents,following activition,the inhibitory units degraded and NF- K B trandfers from cytoplasm to cell nucleus, where its dimmers are free to bind DNA containing special sequence^GGGpuNNpyCC-S') , the transcription of cytokine gene is activated. NF- K B is required formaximal transcription of many cytokines, including IH,IL-6JL-8 , tumor necrosis-a(TNF-a).Clinical investigations suggested that EL-1 ?,IL-6,IL-8 and TNF-a were elevated in the vitreous of different stages of PVR, and those cytokines are significantly related to the progression of PVR_However, the way production of these cytokines in PVR is still uncertain. NF- K B has a significant role in coordinating transcription of these cytokines, production of these cytokines in PVR is may also regulated by activation of NF- K B , NF- K B could be a critical factor which controls the production of these cytokines in PVR, to block activation of NF- K B would be a useful way to prevent the progression of PVR.dexamethasone (DX) has been used in clinic as a auxiliary medcine for therapy of PVR. but the mechanisms of hs effects on PVR are still uncertain.Purpose (D To observe the expression of NF-xB in specimens of PVR. (2) To investigate the relationship between NF-Kfi and proinflammatory factor messenger RNA(mRNA) in periretinal membrane(PRM) of PVR. ?To observe the expression of NF-icB in human retinal epithelial cells(hRPE) and effects of dexamethasone on its expression.Methods ?Vitreous specimens from 29 cases of different stages of PVR were studied, including 13 fluid collections and 16 specimens of PRM. Cytocentrifuge slides of 13 fresh vitreous specimens and paraffin section of PRM were prepared. Immunohistochemical staining was performed to examine the presence of NF- Kfi. (2)16 specimens of periretinal membranes were collected during vitrectomy, The presence of mRNA coding for IL-lp\IL-6,IL-8 and TNF alpha was observed using in situ hybridization(ISH).(I) Cultured hRPE were implanted in 24 well culture plates with a cover slide 1cm2 to prepare slides of cells,which were divided into normal control groups % the Lipolysaccharide(LPS) stimulated groups and groups stimulated with LPS and desamethasone.Then they were photographed after immunohistochemical staining with ABC technique.Results ?NF- K B expression was detected in all 4 cytocentrifuge slids of PVR B grade and 5 PRM of 9 specimens of PVR C grade.There is no NF- K B expression in all specimens of PVR D grade.NF- K B was located in nucleus of all positive cells .?Theexpression of proinflammatory factors mRNA was not found in normal human retina. IL-1 ?mRNA was expressed in 3 specimens of PVR C grade and one specimen of PVR D grade, TNF- a mRNA was expressed in 4 specimens of PVR C grade, there is one specimen of PVR C grade expressed IL-8mRNA, four specimens of PVR C expressed IL-6mRNA.In these positive specimens, one exhibited cells expressing mRNA for...
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