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Updated: Nov 4, 2025
An Optic Nerve Crush Injury Murine Model to Study Retinal Ganglion Cell Survival
Published on: April 25, 2011
Semaphorin3A increases M1-like microglia and retinal ganglion cell apoptosis after optic nerve injury
Liu Yun-Jia1, Chen Xi1, Zhang Jie-Qiong1
1Department of Ophthalmology, Daping Hospital, Army Medical Center, Army Medical University, No. 10, Changjiang Branch, Daping, Yuzhong District, Chongqing, 400042, People's Republic of China.
Background:
The mechanisms leading to retinal ganglion cell (RGC) death after optic nerve injury have not been fully elucidated. Current evidence indicates that microglial activation and M1- and M2-like dynamics may be an important factor in RGC apoptosis after optic nerve crush (ONC). Semaphorin3A (Sema3A) is a classic axonal guidance protein,which has been found to have a role in neuroinflammation processes. In this study, we investigated the contribution of microglial-derived Sema3A to progressive RGC apoptosis through regulating paradigm of M1- and M2-like microglia after ONC.
Method:
A mouse ONC model and a primary microglial-RGC co-culture system were used in the present study. The expression of M1- and M2-like microglial activation markers were assessed by real-time polymerase chain reaction (RT-qPCR). Histological and Western blot (WB) analyses were used to investigate the polarization patterns of microglia transitions and the levels of Sema3A. RGC apoptosis was investigated by TUNEL staining and caspase-3 detection.
Results:
Levels of Sema3A in the mouse retina increased after ONC. Treatment of mice with the stimulating factor 1 receptor antagonist PLX3397 resulted in a decrease of retinal microglia. The levels of CD16/32 (M1) were up-regulated at days 3 and 7 post-ONC. However, CD206 (M2) declined on day 7 after ONC. Exposure to anti-Sema3A antibodies (anti-Sema3A) resulted in a decrease in the number of M1-like microglia, an increase in the number of M2-like microglia, and the amelioration of RGC apoptosis.
Conclusions:
An increase in microglia-derived Sema3A in the retina after ONC partially leads to a continuous increase of M1-like microglia and plays an important role in RGC apoptosis. Inhibition of Sema3A activity may be a novel approach to the prevention of RGC apoptosis after optic nerve injury.
Insights
Microglia-derived Semaphorin3A (Sema3A) drives retinal ganglion cell (RGC) death after optic nerve injury by promoting M1-like microglia. Inhibiting Sema3A may prevent RGC apoptosis.
Area of Science:
- Neuroscience
- Immunology
- Ophthalmology
Background:
- Retinal ganglion cell (RGC) death mechanisms post-optic nerve injury (ONI) are unclear.
- Microglial activation and M1/M2 polarization are implicated in RGC apoptosis.
- Semaphorin3A (Sema3A), an axonal guidance protein, plays a role in neuroinflammation.
Purpose of the Study:
- To investigate the role of microglial-derived Sema3A in RGC apoptosis after optic nerve crush (ONC).
- To determine how Sema3A influences M1/M2 microglial polarization dynamics post-ONC.
Main Methods:
- Mouse ONC model and primary microglial-RGC co-culture.
- RT-qPCR for M1/M2 microglial markers.
- Western blot and TUNEL staining for Sema3A, microglia, and RGC apoptosis.
Main Results:
- Sema3A levels increased post-ONC.
- M1 markers (CD16/32) upregulated; M2 markers (CD206) declined post-ONC.
- Anti-Sema3A treatment reduced M1 microglia, increased M2 microglia, and ameliorated RGC apoptosis.
Conclusions:
- Microglial Sema3A contributes to M1-like microglia increase and RGC apoptosis after ONC.
- Sema3A inhibition is a potential therapeutic strategy for preventing RGC loss in optic nerve injury.
