摘要目的 观察探讨FTY720对糖尿病大鼠视网膜血管内白细胞粘附和血管通透性的影响及机制.方法 雄性Wistar大鼠90只,随机分为正常对照组、糖尿病组和FTY720组,每组30只.糖尿病组和FTY720组大鼠采用一次性腹腔注射链脲佐菌素的方法建立糖尿病模型.建模成功后,FTY720组大鼠以0.3 mg/kg的剂量灌胃给予FTY720,1次/d,连续3个月.于FTY720组大鼠干预后3个月,3组大鼠均用于相关实验.采用免疫组织化学染色法观察大鼠视网膜细胞间粘附分子1(ICAM-1)和血管细胞粘附分子1(VCAM-1)的表达,并计数阳性细胞数;荧光定量逆转录聚合酶链反应(RT-PCR)检测大鼠视网膜ICAM-1、VCAM-1的mRNA表达;异硫氰酸荧光素标记的刀豆素蛋白灌注染色法检测大鼠视网膜血管内白细胞粘附情况;伊凡思蓝(EB)灌注染色法观察大鼠视网膜EB渗漏情况并定量;免疫荧光染色法检测视网膜炎性细胞浸润情况.结果 糖尿病组大鼠视网膜ICAM-1(t=12.81)、VCAM-1(t=11.75)阳性细胞数及ICAM-1(t=16.14)、VCAM-1(t=9.59)mRNA表达均较正常对照组明显增加,差异均有统计学意义(P＜0.05);FTY720组大鼠视网膜ICAM-1(t=-9.93)、VCAM-1(t=-6.61)阳性细胞数及ICAM-1(t =-15.28)、VCAM-1(t=一6.10)mRNA表达较糖尿病组明显减少,差异有统计学意义(P＜0.05).糖尿病组大鼠视网膜血管内粘附的白细胞计数(t=16.32)及平均EB渗漏量(t=17.83)较正常对照组明显增加,差异有统计学意义(P＜0.05);FTY720组大鼠视网膜血管内粘附的白细胞计数(t=-9.93)及平均EB渗漏量(t=-11.82)较糖尿病组明显减少,差异有统计学意义(P＜0.05).糖尿病组大鼠视网膜可见大量CD45阳性的白细胞浸润,其中CD11b阳性的巨噬细胞和(或)活化的小胶质细胞数量明显增多.FTY720组大鼠视网膜可见少量CD45阳性的白细胞浸润以及少量CD11b阳性的巨噬细胞和(或)活化的小胶质细胞.结论 FTY720可减少糖尿病大鼠视网膜血管内白细胞粘附,降低血管通透性.其机制可能与下调视网膜ICAM-1和VCAM-1的表达有关.

abstractsObjective To evaluate the effect of FTY720 on retinal leukocytes adhesion and vascular permeability in diabetic retinopathy (DR) model,and explore its mechanism.Methods Ninety male Wister rats were randomly divided into normal control group,diabetic group and FTY720 group,thirty rats in each group.Diabetes was induced by giving a single intraperitoneal injection of streptozocin.FTY720 group was administered with FTY720 at a dose of 0.3 mg/kg by oral gavage daily for 3 months after establishment of diabetes.All rats were used for experiments following intervention for 3 months in FTY720 group.Immunohistochemical staining was used to observe the expression and distribution of intercellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1),and the positive cells were counted.Real-time reverse transcription PCR was used to measure mRNA expression of ICAM-1 and VCAM-1.Fluorescein isothiocyanate-Concanavalin A perfusion was used to detect retinal leukocytes adhesion.Evans blue (EB) perfusion was used to analyze retinal vascular permeability.Immunofluorescence staining was used to detect retinal inflammatory cells infiltration.Results In diabetic group,both ICAM-1(t =12.81) and VCAM-1 (t=11.75) positive cells as well as their mRNA expression (t=16.14,9.59) were increased compared with normal control group,with statistical significance (P＜ 0.05).In FTY720 group,both ICAM-1(t=-9.93) and VCAM-1 (t=-6.61) positive cells as well as their mRNA expression (t=-15.28,-6.10) were decreased compared with diabetic group,with statistical significance (P＜ 0.05).Retinal leukocytes adhesion (t=16.32) and EB permeability (t=17.83) were increased in diabetic group compared with normal control group,while they were decreased in FTY720 group compared with diabetic group(t=-9.93,-11.82),with statistical significance (P＜0.05).There were many CD45 positive leukocytes infiltration in retina of diabetic group,including CD11b positive macrophage/activated microglia,while both of them were little in FTY720 group.Conclusions FTY720 can decrease retinal leukocytes adhesion,reduce retinal vascular permeability and inflammatory cells infiltration,which is associated with down-regulation of ICAM-1 and VCAM-1.