An organotypic model for investigating drug-radiation responses in the lung.

BACKGROUND

Established radiobiological models are commonly used to assess anti-tumor effects and normal tissue toxicity. However, these models have notable limitations, and additional models are necessary to gain a deeper insights into drug-radiation interactions.

OBJECTIVE

This study aimed to develop an organotypic model by using precision-cut lung slices (PCLSs) to evaluate radiation-induced residual deoxyribonucleic acid (DNA) damage, both alone and in combination with a pharmacological inhibitor of DNA double-strand break (DSB) repair.

METHODS

Left lungs from female C57BL/6 mice were dissected, perfused with 4% low-gelling-temperature agarose, and sliced into 250 μm sections. Lung slices were then incubated for up to 7 days. The slices were irradiated using Cs, either with or without a DNA-dependent protein kinase (DNA-PK) inhibitor (NU7441). Tissue sections were subsequently fixed and stained for γH2AX and 53BP1, which serve as histological markers of DNA DSBs.

RESULTS

The established conditions preserved tissue viability for up to 7 days and maintained structural integrity for 2 days. DNA damage, detected through γH2AX and 53BP1 staining, was consistent between lungs irradiated and their counterparts irradiated . In the organotypic model, radiation alone in DNA-PK-deficient SCID mice and radiation combined with DNA-PK inhibition in C57BL/6 mice led to increased residual γH2AX and 53BP1 staining.

CONCLUSION

This study demonstrates that residual DNA damage levels following ionizing radiation in lung tissue are comparable between and tissue slices, suggesting that PCLSs serve as a valuable organotypic model for investigating the effects of drug-radiation combinations.