Table 9.
Recommendations for cell culture and animal experiments for dose rate analysis
| Consideration | Recommendation |
|---|---|
| 1.Cell/tissue/species type | Conditions appropriate for experiment and measured endpoint are essential. Investigators need to recognise the importance of experimental systems and endpoints that are adequate for investigating the question |
|
a.Cell line or primary cell or b.Animal strain/model |
Use normal primary cells for assessing normal tissue response; consider cell/tissue-specific response; use appropriate genetic alteration |
| c.Age/sex of donor/organism | Use a variety, including multiple donors, to confirm consistency of results (or determine factors that could lead to result in higher response) |
| 2.Cell culture conditions | Culture conditions that are consistent and relevant to physiological conditions appropriate for the endpoints |
| a.Confluence | In vivo, cells will usually be confluent with low proliferation rates. Awareness of the effects of culturing cells is essential |
| b.Proliferation | |
| c.Oxygen concentration | Use normoxic conditions for very low doses |
| d.Routine | Maintain consistency (e.g., timing of harvesting/media changes) |
| 3.Animal experiments | Ensure the model chosen is appropriate to the endpoint being investigated |
| a.Experimental design | Include randomised, appropriate controls that are matched for exposure conditions to irradiated samples. Sham-irradiated controls are needed for all animal experiments |
| b.Housing conditions | Consider best practice for animal welfare, plus variability introduced via cage mates, enrichment, light, noise, etc. |
| c.Other stress/variability | Reduce sources of stress (e.g., handing and transport of experimental animals) |
| 4.Ionising radiation exposure | Ensure consistency and appropriate controls |
| a.Dose rate | Use multiple dose rates to observe dose rate effects, including physiologically relevant LDR |
| b.Cumulative dose | Include controls to distinguish dose-rate effect from total cumulative dose received |
| c.Radiation type | Keep exposure type the same to be able to compare between studies |
| 5.Readout/endpoint | Select appropriately and use a variety to confirm effects |
| 6.Molecular (‘omics’, genomic instability, chromosome aberration, histone modifications) | Validate molecular changes using appropriate functional assay |
| 7.Cancer (mutation/unrepaired DNA damage, inflammation, cell death) | Consider sensitivity of assay, suitability to answer question, other contributing factors |
| 8.Non-cancer (inflammation, senescence, altered proliferation, epigenetic age) |