In Vivo Imaging of Radiation-Induced Apoptosis at Single-Cell Resolution in Transgenic Zebrafish Embryos

Area of Science:

• Cell Biology
• Developmental Biology
• Radiation Biology

Background:

• Apoptosis is a key regulated cell death pathway induced by ionizing radiation.
• Studying radiation-induced apoptosis in vivo is crucial for understanding physiological responses but faces imaging challenges.
• Zebrafish offer optical transparency and genetic tractability, making them suitable for in vivo apoptosis research.

Purpose of the Study:

• To develop a transgenic zebrafish model for visualizing radiation-induced apoptosis in real-time.
• To investigate the dynamics of apoptosis and apoptotic cell clearance in response to ionizing radiation.
• To establish a versatile in vivo system for studying radiation-induced cell death.

Main Methods:

• Generation of a secA5 transgenic zebrafish line expressing secreted ANNEXIN V fused with mVenus.
• In vivo imaging of zebrafish embryos and larvae following 2 Gy total-body irradiation.
• Single-cell resolution imaging and quantification of apoptosis in various tissues, including the brain.

Main Results:

• Radiation-induced apoptosis was successfully visualized at single-cell resolution throughout the zebrafish embryo.
• Elevated apoptosis was quantified in the embryonic and larval brain neuroepithelium and parenchyma.
• Microglial clearance of apoptotic cells in the larval brain was imaged in real-time.

Conclusions:

• The secA5 transgenic zebrafish is an effective in vivo system for studying radiation-induced apoptosis.
• This model allows dynamic visualization and quantification of apoptosis and phagocytic clearance.
• It provides a versatile platform for investigating radiation effects on cell death and tissue repair.