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Updated: Aug 30, 2026
Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System
Published on: May 12, 2011
Generation of retinal ganglion cells is modulated by caspase-dependent programmed cell death
Raquel Mayordomo1, Ana I Valenciano, Enrique J de la Rosa
1Department of Neuroscience, Uppsala University, Uppsala, Sweden.
Abstract:
Programmed cell death occurs during both early and late neural development. The mechanisms for the regulation and execution of the early cell death as well as its developmental role are still not fully understood. In this work we have studied the early programmed cell death in the retinal neuroepithelium. Apoptotic cells were selectively located around the optic nerve head in the retinal neuroepithelium of 2- to 6-day-old chick embryos. TUNEL-positive cells and cells which were immunostained for activated caspase-3 showed overlapping distributions suggesting that caspase-3 is involved in the early retinal cell death. Caspase-3 involvement in early retinal cell death was also demonstrated by in vivo treatment with caspase inhibitors z-DEVD-fmk and Boc-D-fmk. After 6 h of treatment, the number of TUNEL-positive cells was reduced by 50%. Sustained treatments (20 h) resulted in a slight widening in the central part of the neural retina but the retinal ganglion cell axons maintained their organization and navigation towards the optic fissure. The most prominent result after inhibition of cell death was an increase in the number of retinal ganglion cells which also produced an enlargement of the ganglion cell layer and an increased number of ganglion cell axons. In conclusion, our results show that caspase-dependent programmed cell death occurs in the embryonic chick retina and that it plays a role to modulate the generation of retinal ganglion cells.
Insights
Early programmed cell death in chick retinas involves caspase-3. Inhibiting this cell death increases retinal ganglion cells, suggesting a role in modulating their generation.
Area of Science:
- Neuroscience
- Developmental Biology
- Cell Biology
Background:
- Programmed cell death is crucial in neural development, but its early mechanisms and roles remain unclear.
- Early programmed cell death in the retinal neuroepithelium is not fully understood.
- This study investigates early programmed cell death in embryonic chick retinal development.
Purpose of the Study:
- To investigate the mechanisms and role of early programmed cell death in the retinal neuroepithelium.
- To identify the specific caspases involved in early retinal cell death.
- To determine the impact of inhibiting early cell death on retinal development.
Main Methods:
- TUNEL staining and immunostaining for activated caspase-3 to locate apoptotic cells.
- In vivo treatment with caspase inhibitors (z-DEVD-fmk and Boc-D-fmk).
- Analysis of cell death markers, retinal structure, and retinal ganglion cell numbers after inhibitor treatment.
Main Results:
- Apoptotic cells were concentrated around the optic nerve head in embryonic chick retinas.
- Activated caspase-3 and TUNEL-positive cells showed overlapping distributions, indicating caspase-3 involvement.
- Caspase inhibition significantly reduced TUNEL-positive cells and increased retinal ganglion cell numbers and axons.
Conclusions:
- Caspase-dependent programmed cell death occurs in the embryonic chick retina.
- This cell death process plays a role in modulating the generation of retinal ganglion cells.
- Inhibiting early retinal cell death leads to an increase in retinal ganglion cells.
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