ABSTRACT
Background The retina microglia play a eliminating effect on apoptotie cells in the neural retinal layer of normal rats during postnatal development.Milk fat globule epidermal growth factor 8(MFG.E8)can combine specifically with phosphatidylinositol serine of the surface of apoptotie 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,Pi4,P30,P45 groups according to their postnatal days,and the 30-day-old RCS rats(2 rats)served as controls.Double stain of M FG.E8 and microglial cells marker(CD11b)was performed by immunofluorescence.Expressions of MFG-E8,integrin β5,CD11b 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-labeled lgG respectively in normal adult rats.RT-PCR showed that the mRNA of MFG-E8,integrin 85,CD11b and IL-6 was detectable at P0 rats.The expression level of these eytokines began to rise fterward 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.