Imaging the radioprotective effect of amifostine in the developing brain using an apoptosis-reporting transgenic zebrafish

Abstract

Purpose

Normal tissue radioprotectants alleviate radiation-induced damages and preserve critical organ functions. Investigating their efficacy in vivo remains challenging, especially in enclosed organs like the brain. An animal model that enables direct visualization of radiation-induced apoptosis while possessing the structural complexity of a vertebrate brain facilitates these studies in a precise and effective manner.

Materials and methods

We employed a secA5 transgenic zebrafish expressing secreted Annexin V fused with a yellow fluorescent protein to visualize radiation-induced apoptosis in vivo. We developed a semi-automated imaging method for standardized acquisition of apoptosis signals in batches of zebrafish larvae. Using these approaches, we studied the protective effect of amifostine (WR-2721) in the irradiated zebrafish larval brain.

Results

Upon 2 Gy total-body ¹³⁷Cs irradiation, increased apoptosis could be visualized at high resolution in the secA5 brain at 2, 24, and 48 hour post irradiation (hpi). Amifostine treatment (4 mM) during irradiation reduced apoptosis significantly at 24 hpi and preserved Wnt active cells in the larval brain. When the 2 Gy irradiation was delivered in combination with cisplatin treatment (0.1 mM), the radioprotective effect of amifostine was also observed.

Conclusions

Our study reveals the radioprotective effect of amifostine in the developing zebrafish larval brain, and highlights the utility of secA5 transgenic zebrafish as a novel system for investigating normal tissue radioprotectants in vivo.

Keywords:

• Radiation
• cell death
• apoptosis
• Wnt signaling
• progenitors
• amifostine
• cisplatin

Acknowledgement

We sincerely thank Cathleen Teh and Thorsten Wohland for sharing with us the Tg(7xTCF-Xla.Siam:nlsmCherry)^ia5 transgenic fish.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Research Foundation (NRF) funding to the Singapore Nuclear Research and Safety Initiative (RIE2020 and RIE2025 grants to H.S.). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Notes on contributors

Lucas W.H. Sun

Lucas W.H. Sun worked as a researcher in Singapore Nuclear Research and Safety Initiative, National University of Singapore. His research focused on in vivo imaging of radiation-induced apoptosis in transgenic zebrafish. He is now pursuing postgraduate medical degree.

Halida Thanveer Asana Marican

Halida Thanveer Asana Marican is a researcher in Singapore Nuclear Research and Safety Initiative, National University of Singapore. She investigates chromosome aberrations, cell death, innate immune response and their dynamic interplay in irradiated zebrafish.

Lih Khiang Beh

Lih Khiang Beh is a researcher in Singapore Nuclear Research and Safety Initiative, National University of Singapore. He uses transgenic zebrafish to dissect the in vivo dynamics of radiation-induced DNA damage foci in various cell populations under natural physiology.

Hongyuan Shen

Hongyuan Shen is a senior researcher in Singapore Nuclear Research and Safety Initiative, National University of Singapore. She leads the zebrafish radiobiology team. Her journey with zebrafish dates back to the start of her PhD, and she has been fascinated by them ever since.