PEDF对氧诱导视网膜病变小鼠视网膜MCP-1表达的影响

Effects of PEDF on the expression of MCP-1 in mice retina of oxygen-induced retinopathy

摘要:

目的：观察色素上皮衍生因子(pigment epithelium-derived factor，PEDF)在氧诱导视网膜病变(oxygen-induced retinopathy，OIR)中对小鼠视网膜新生血管(retinal neovascularization，RNV)和单核细胞趋化因子-1(monocyte chemoattractant protein-1，MCP-1)表达的影响，探讨PEDF对缺血缺氧性视网膜病变的保护作用和机制。

方法：取7日龄C57BL/6J新生小鼠160只，将120只7日龄小鼠与哺乳母鼠共同置于氧浓度为(75±2)%的氧环境内饲养5d，然后返回正常氧环境中饲养5d，建立OIR模型； 40只小鼠始终置于正常氧环境饲养。分别于12日龄和14日龄给予PEDF药物治疗组小鼠右眼玻璃体腔注射PEDF(2μg/μL)各1μL，给予PBS治疗对照组和正常对照组小鼠右眼玻璃体腔注射等量的磷酸盐缓冲液(phosphate buffered saline，PBS)。所有小鼠于17日龄麻醉处死后取视网膜，采用视网膜铺片和Lectin染色法观察各组小鼠病理性新生血管的生成情况； Western-blot检测PEDF和MCP-1蛋白在各组小鼠视网膜的表达； 实时荧光定量逆转录多聚酶链反应(RT-PCR)检测各组小鼠视网膜PEDF和MCP-1 mRNA的表达。

结果：视网膜铺片和Lectin染色结果显示OIR模型组RNV面积较正常组显著增大，差异有统计意义(P<0.01)，PEDF药物治疗组RNV面积较PBS治疗对照组明显减小，差异有统计意义(P<0.01)。Western-blot和RT-PCR结果显示，OIR模型组MCP-1蛋白和mRNA的表达水平均明显高于正常组，差异有统计意义(均P<0.05)； OIR模型组PEDF蛋白和mRNA的表达水平均明显低于正常组，差异有统计意义(均P<0.01)； PEDF药物治疗组MCP-1蛋白和mRNA的表达量较PBS治疗对照组均显著减少，差异有统计意义(均P<0.05)； PEDF药物治疗组MCP-1蛋白和mRNA的表达量较正常对照组升高，但差异均无统计学意义(均P>0.05)。

结论：PEDF能够抑制OIR小鼠视网膜新生血管形成，同时下调MCP-1在OIR小鼠视网膜的表达，后者可能是其抑制新生血管形成从而发挥视网膜保护作用的机制之一。

Abstract:

AIM: To observe the effect of pigment epithelium-derived factor(PEDF)on retinal neovascularization(RNV)and monocyte chemoattractant protein-1(MCP-1)expressions in mice retina of oxygen-induced retinopathy(OIR), and to investigate the protective effect of PEDF on ischemia hypoxia retinopathy and the possible mechanism.

METHODS: A total of 160 postnatal day(P)7 C57BL/6 mice were obtained. All mice except normal control group were exposed to(75±2)% oxygen environment for 5d and then kept in room air for another 5d to establish the OIR mice model. All mice in normal control group(40 mice)were exposed to room air only. At P12 and P14, respectively, mice in PEDF treatment group were injected intravitreously with recombinant human PEDF(2μg/eye,1μL)in the right eye, while mice in treatment control group were injected intravitreously with the same volume of vehicle [1μL, 10mmol/L phosphate buffered saline(PH7.4), PBS] in the right eye. All mice were euthanized at P17. Eyes were whole mounted and stained with Lectin to observe the growth of abnormal RNV; And retinal specimens were prepared for PEDF, MCP-1 protein and mRNA analysis by Western blot and real time RT-PCR respectively.

RESULTS: Changes of retinal vessels had been detected by fluorescence microscopy on flat-mounted retina. The relative RNV areas were significantly increased in OIR model group compared with those in normal control group(P<0.01). However, the relative RNV areas were significantly reduced in PEDF treatment group compared with those in PBS treatment control group(P<0.01). The specific expression of MCP-1 protein and mRNA in the OIR model group were higher than those of normal control group, presenting a statistically significance(both P<0.05). The specific expression of PEDF protein and mRNA in the OIR model group showed a considerable decline in comparison with normal control group, presenting a statistically significance(both P<0.01). And the specific expression of MCP-1 protein and mRNA in those of PEDF-treated group showed a considerable decline in comparison with PBS-treated group, and the differences were statistically significant(both P<0.05). However, there were increase of the expression of MCP-1 protein and mRNA between normal control group and PEDF-treated group, presenting no statistically significance(both P>0.05).

CONCLUSION: PEDF could inhibit oxygen-induced retinal neovascularization and down-regulate retinal MCP-1 expression under hypoxia, which may underlie its anti-neovascularization effects and play a role of protection in ischemic retinopathy.