| [Background ] Diabetic retinopathy(DR) is one of the commonest and severest complications in diabetes mellitus, and also the main cause of blindness. The pathogenesis is complicated, it maybe is related to such reasons as: 1 the abnormal metabolism of polyol-Inositol; 2 free radical; 3 no-enzymatic glycation reaction of protein; 4 activation of DG-PKC system; 5 action of cytokine; 6 local rennin-angiotensin. That protein react with glucose can product irreversibility end-products, it is called advanced glycation end products (AGEs). AGEs is not only the products of diabetes, but also act as one of medium, can induce extensive abnormal reaction in cells and tissue such as unreasonable expression of growth factor, accumulation of extracellular matrix (ECM), regulation dysfunction of blood vessel, etc. AGEs can extensively accumulate in ocular tissue, act on retinal endothelial cell, retinal pericytes, pigment epithelial(RPE)cells and Muller cells, etc, play an important role in DR. Many study indicated that VEGF is the most important and direct factor to stimulate vessel growth, and play an important role in neovascularization. Meantime, the process is related to the Matrix Metalloproteinase (MMPs) and its inhibitor of TIMPs. So the degradation of ECM by the activation of MMPs is one of the important regulation reasons of biochemistry and cytology. Meanwhile, renin-angiotensin system (RAS) is related closely to DR. In DR, local RAS is activated, andis related to the macular edema and neovascularization, etc. Studying the relation between RAS and DR can help understand the pathogenesis of DR. Meantime, RPE cells is one of the contents of proliferation membrane of PDR and play an important role in it. So we studied the action of AGEs on RPE cell in DR, tried to find it's cellular and molecular mechanism.[Objective! Study the effect of expressing VEGFinRNA of AGEs acting on RPE cells, and the effect of RPE cells producting MMPs and angiotensin acted by AGEs and VEGF individually, to make clearly the mechanism of AGEs in DR.[Methods] The experiment consist of four parts. The first: Human RPE cells were isolated and cultured in vitro, and was evaluated by immunohistochemistry. AGEs and it's contrast was prepared; The second: different concentration of AGEs acted on RPE cells for the same tiine(18h), and the same concentration of AGEs (100ug/inl) acted on RPE cells for different time, the VEGFmRNA were detected by hybridization in situ, and the picture was analyzed by computer image analysis meter. The third: the different concentration of AGEs and VEGF acted on RPE cells for 24h and 28h individually, the same concentration of AGEs(100ug/mDand VEGF (100ng/ml) acted on RPE cells for different time, the MMPs in the culture medium was measured by zymogram. The fourth: the different concentration of AGEs and VEGF acted on RPE cells for24h and 28h individually, the same concentration of AGEs (100ug/ml) and VEGF (100ng/ml) acted on RPE cells for different time, the A I and AII in the culture medium was measured by radioimmunoassay.[Results] l.The human RPE cells were successfully isolated and cultured in vitro, AGEs and it's contrast was prepared. 2. The different concentration of AGEs acted on RPE cells for 18h, we can found the expression of VEGFinRNA gradually increased; lOOug/ml AGEs acted on RPE cells for different time, the expression of VEGFinRNA was found in 2h, and gradually increased as the stimulation time extended among 18h. 3. The different concentration of AGEs acted on RPE cells for 24h, the expression of MMP-2 increased gradually; lOOug/ml AGEs acted on RPE cells for different time, the expression of MMP-2 increased gradually as the stimulation time extended among 48h; the different concentration of VEGF acted on RPE cells for 28h, the expression of MMP-2 increased gradually, lOOng/ml VEGF acted on RPE cells for different time, the expression of MMP-2 increased gradually as the stimulation time extended among 48h; MMP-9 was not found in all groups. 4.AGEs and VEGF acted on RPE cells, all g...
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