Macrophages during retina and optic nerve development in the mouse embryo: relationship to cell death and optic fibres

Anat Embryol (Berl). 2005 Nov;210(4):303-16. doi: 10.1007/s00429-005-0051-3. Epub 2005 Nov 12.


We compared the spatial and temporal patterns of distribution of macrophages, with patterns of naturally occurring cell death and optic fibre growth during early retina and optic nerve development, in the mouse. We used embryos between day 10 of embryogenesis (E10; before the first optic fibres are generated in the retina) and E13 (when the first optic fibres have crossed the chiasmatic anlage). The macrophages and optic axons were identified by immunocytochemistry, and the apoptotic cells were detected by the TUNEL technique, which specifically labels fragmented DNA. Cell death was observed in the retina and the optic stalk long before the first optic axons appeared in either region. Subsequently, specialized F4/80-positive phagocytes were detected in chronological and topographical coincidence with cell death, which disappeared progressively. As development proceeded, the pioneer ganglion cell axons reached the regions where the macrophages were located. As the number of optic fibres increased, the macrophages disappeared. Therefore, cell death, accompanied by macrophages, preceded the growth of fibres in the retina and the optic nerve. Moreover, these macrophages synthesized NGF and the optic axons were p75 neurotrophin receptor (p75(NTR))- and TrkA-positive. These findings suggest that macrophages may be involved in optic axon guidance and fasciculation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Differentiation / analysis
  • Apoptosis*
  • Axons / immunology
  • Axons / metabolism
  • Cell Differentiation
  • Macrophages / cytology
  • Macrophages / physiology*
  • Mice
  • Nerve Fibers / immunology
  • Nerve Fibers / metabolism
  • Nerve Growth Factor / analysis
  • Nerve Growth Factor / metabolism
  • Optic Nerve / embryology*
  • Optic Nerve / immunology
  • Receptor, Nerve Growth Factor / analysis
  • Receptor, Nerve Growth Factor / metabolism
  • Receptor, trkA / analysis
  • Receptor, trkA / metabolism
  • Retina / embryology*
  • Retina / immunology
  • Time Factors


  • Antigens, Differentiation
  • Receptor, Nerve Growth Factor
  • monocyte-macrophage differentiation antigen
  • Nerve Growth Factor
  • Receptor, trkA