中文摘要：

背景神经层视网膜小胶质细胞在视网膜胚胎后期发育过程中起“清道夫”的作用，可清除凋亡细胞。乳脂球上皮生长因子18（MFG—E8）能特异性地与凋亡细胞表面的磷酯酰丝氨酸相结合，增强巨噬细胞对凋亡细胞的吞噬作用。目的观察MFG—E8及相关细胞因子在正常大鼠神经层视网膜胚胎后期发育过程中的表达。方法取清洁级鼠龄为0、3、7、14、30、45d的正常皇家外科学院（RCS）大鼠各5只。免疫荧光双标染色标记MFG—E8和小胶质细胞标志物CD11b，荧光实时定量聚合酶链反应（real—time PCR）检测正常大鼠各组视网膜中MFG—E8、整合素135、CD11b、白细胞介素-6（IL-6）mRNA的表达变化。结果MFG—E8免疫阳性细胞分布于视网膜内层，主要为视网膜节细胞层和外丛状层，与CD11b染色部位相同。Real—time PCR检测发现，在出生后即可检测到MFG-E8、整合素β5、CD11b及IL-6 mRNA的表达，其表达量在出生后早期较低，然后逐渐增加，鼠龄14d组的mRNA表达最强烈，然后逐渐下降。鼠龄14d组的各因子mRNA表达水平明显高于其他鼠龄组，差异均有统计学意义（P〈0．01）。结论MFG—E8特异地表达于正常RCS大鼠神经层的视网膜小胶质细胞，表达量出生后呈先升高后降低，14d为高峰的规律。

英文摘要：

Background The retina mieroglia play a eliminating effect on apoptotic cells in the neural retinal layer of normal rats during postnatal development. Milk fat globule epidermal growth factor 8 （MFG-ES） can combine specifically with phosphatidylinositol serine of the surface of apoptotic cells and enhance macrophage phagoeytosis of apoptotic cells. Objective Present study was to evaluate the localization and expression of MFG- E8 and its relevant cytokines in the neural retinal layer of normal rats during postnatal development. Methods Normal royal college of surgeon （RCS） rats were divided into P0, P3, P7, P14, P30, P45 groups according to their postnatal days,and the 30-day-old RCS rats （2 rats） served as controls. Double stain of MFG-E8 and microglial cells marker （CDllb） was performed by immunofluorescence. Expressions of MFG-E8, integrin [55, CDllb and interleukin-6 （IL-6） mRNA in the neural retina were analyzed by real-time quantitative reverse transcription polymerase chain reaction （RT-PCR）. The utilization of animals complied with the Regulation for the Administration of Affair Concerning Experimental Animals by State and Science and Technology Commission. Results MFG-E8 and CD11b were positively co-expressed in retinal ganglion cell layer and external plexiform layer with the green fluorescence for FITC-labeled IgG and red fluorescence for cy3-1abeled IgG respectively in normal adult rats. RT-PCR showed that the mRNA of MFG-E8, integrin β5, CD11b and IL-6 was detectable at P0 rats. The expression level of these cytokines began to rise afterward and reached peak value at P14 rats and then declined gradually, showing significant differences among different ages groups in various cytokines mRNA expression （all P 〈 0.05 ）. Conclusion MFG-E8 can be specifically expressed in the neural layer of retina microglia in RCS rat.