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Updated: Jul 28, 2026
In Vivo Dynamics of Retinal Microglial Activation During Neurodegeneration: Confocal Ophthalmoscopic Imaging and Cell Morphometry in Mouse Glaucoma
Published on: May 11, 2015
Appearance of microglial cells in the postnatal rat retina
J Boya1, J Calvo, A L Carbonell
1Department of Histology, Faculty of Medicine, University Complutense, Madrid, Spain.
Abstract:
The development of microglial cells in the postnatal rat retina is described using histochemical techniques for acid phosphatase and peroxidase as well as silver impregnations for microglia. On the second postnatal day, round acid phosphatase-positive macrophages appeared on the vitreal surface of retina, locating themselves close to developing blood vessels. Later, microglial precursors invaded retinal tissues, reaching the outer plexiform layer by the tenth postnatal day. In all stages studied, microglia or their precursors were peroxidase-negative. The transformation of round microglial precursors into adult ramified microglia is also described. Owing to the relation found between developing microglia and blood vessels, a vascular origin is proposed for the retinal microglial cells.
Insights
Retinal microglia originate from vascular precursors, appearing as macrophages near blood vessels and migrating inward. These cells mature into ramified microglia, remaining peroxidase-negative throughout development.
Area of Science:
- Neuroscience
- Ophthalmology
- Developmental Biology
Background:
- Microglia are the primary immune cells of the central nervous system.
- Their developmental origins and early characteristics in the retina are not fully understood.
- Understanding microglial development is crucial for retinal health and disease research.
Purpose of the Study:
- To describe the developmental process of microglial cells in the postnatal rat retina.
- To investigate the origin and morphological transformation of retinal microglia.
- To determine the relationship between microglia and developing retinal vasculature.
Main Methods:
- Histochemical techniques including acid phosphatase and peroxidase staining.
- Silver impregnation methods for visualizing microglia.
- Microscopic analysis of retinal tissue at various postnatal days.
Main Results:
- Acid phosphatase-positive macrophages appeared on postnatal day 2 near developing blood vessels.
- Microglial precursors invaded retinal tissue, reaching the outer plexiform layer by day 10.
- Microglia and their precursors were consistently peroxidase-negative; transformation from round precursors to ramified adult forms was observed.
Conclusions:
- Retinal microglial cells originate from vascular precursors.
- The study details the migration and maturation process of microglia in the developing rat retina.
- A vascular origin for retinal microglia is proposed based on observed associations with blood vessels.
