2型糖尿病视网膜病变患者外周血单个核细胞中PEDF与TNF-α水平的变化

 目的:色素上皮衍生因子（PEDF）是影响糖尿病视网膜病变（DR）发生发展的重要因子，本研究观察2型糖尿病视网膜病变患者外周血单个核细胞（PBMCs）中PEDF、磷酸化NF-κB p65及TNF-α的表达，探讨DR的发病机制。方法:选取2011年10月~2013年4月在我院内分泌科住院确诊为2型糖尿病的患者(DM组)108例，并根据眼底造影结果将患者分为无糖尿病视网膜病变组（NDR组）52例和糖尿病视网膜病变组（DR组）56例，同期糖耐量实验正常者52例作为对照组（NC组）。密度梯度离心法收集患者 PBMCs，提取总蛋白，Western blotting检测3组患者PBMCs中PEDF、磷酸化NF-κB p65和TNF-α蛋白表达水平，ELISA测定血浆PEDF与TNF-α水平，收集患者体检指标并测量患者生化指标。结果:Western blotting检测结果显示NDR组和DR组PEDF、磷酸化NF-κB p65和TNF-α蛋白水平明显高于NC组（P<0.05）；DR组TNF-α蛋白水平明显高于NDR组（P<0.05），DR组PEDF及磷酸化NF-κB p65蛋白水平略高于NDR组，差异无统计学意义（P>0.05）；NDR组和DR组血浆PEDF与TNF-α水平均明显高于NC组（P<0.05）,DR组明显高于NDR组（P<0.05）。在糖尿病组，血浆PEDF水平与TNF-α及血尿酸水平呈正相关（r=0.39，r=0.25，P<0.05）。结论:本研究首次证实PBMCs中可表达PEDF；2型糖尿病患者PBMCs中PEDF表达水平增加，TNF-α及血浆PEDF的表达水平上调，PEDF可能通过与炎症因子TNF-α相互作用影响DR发生发展。

Levels of PEDF and TNF-α in PBMCs of type 2 diabetic retinopathy patients

AIM:To investigate the roles of pigment epithelium-derived factor (PEDF), phosphorylated NF-κB p65 and TNF-α in peripheral blood mononuclear cells (PBMCs) in diabetic retinopathy (DR) patients. METHODS:Fifty-two healthy persons were enrolled in the study as normal control group (NC group). Type 2 diabetic patients served as DM group (n=108), which were sub-divided into non-diabetic retinopathy group (NDR group, n=52) and diabetic retinopathy group (DR group, n=56) by angiography. The PBMCs were isolated by the technique of density-gradient centrifugation. The protein levels of PEDF, phosphorylated NF-κB p65 and TNF-α in the PBMCs were determined by Western blotting. The levels of plasma PEDF and TNF-α were detected by ELISA. The content of serum uric acid (SUA) and white blood cell count were measured. RESULTS:The levels of PEDF, TNF-α and phosphorylated NF-κB p65 in the PBMCs were statistically higher in NDR group and DR group than those in control group. The level of TNF-α increased significantly in DR group as compared with NDR group. The levels of PEDF and phosphorylated NF-κB p65 were slightly but not significantly higher in DR group than those in NDR group. The plasma levels of PEDF and TNF-α were evidently elevated in NDR group and DR group compared with NC group, and those were obviously higher in DR group than those in NDR group. In the diabetic patients, the plasma level of PEDF was positively correlated with the levels of TNF-α (r=3.39, P<0.05) and SUA (r=0.25, P<0.05). CONCLUSION:The expression of PEDF in PBMCs is markedly increased, accompanied with the elevation of phosphorylated NF-κB p65 and TNF-α in type 2 diabetic patients especially with DR, suggesting that PEDF is possibly involved in the development of DR by inflammatory mechanism.