Effects of Synchrotron X-Ray Micro-beam Irradiation on Normal Mouse Ear Pinnae.
- Potez M Institute of Anatomy, University of Bern, Bern, Switzerland.
- Bouchet A Institute of Anatomy, University of Bern, Bern, Switzerland.
- Wagner J Institute of Anatomy, University of Bern, Bern, Switzerland.
- Donzelli M Biomedical Beamline, European Synchrotron Radiation Facility, Grenoble, France; Joint Department of Physics, The Institute of Cancer Research and the Royal Marsden Hospital, London, United Kingdom.
- Bräuer-Krisch E Biomedical Beamline, European Synchrotron Radiation Facility, Grenoble, France.
- Hopewell JW Green Templeton College, University of Oxford, Oxford, United Kingdom.
- Laissue J Institute of Anatomy, University of Bern, Bern, Switzerland.
- Djonov V Institute of Anatomy, University of Bern, Bern, Switzerland. Electronic address: valentin.djonov@ana.unibe.ch.
- 2018-03-22
Published in:
- International journal of radiation oncology, biology, physics. - 2018
Animals
Dose-Response Relationship, Radiation
Ear
Female
Mice
Mice, Inbred C57BL
Organ Specificity
Radiation Injuries, Experimental
Synchrotrons
Time Factors
X-Ray Therapy
English
PURPOSE
To analyze the effects of micro-beam irradiation (MBI) on the normal tissues of the mouse ear.
METHODS AND MATERIALS
Normal mouse ears are a unique model, which in addition to skin contain striated muscles, cartilage, blood and lymphatic vessels, and few hair follicles. This renders the mouse ear an excellent model for complex tissue studies. The ears of C57BL6 mice were exposed to MBI (50-μm-wide micro-beams, spaced 200 μm between centers) with peak entrance doses of 200, 400, or 800 Gy (at ultra-high dose rates). Tissue samples were examined histopathologically, with conventional light and electron microscopy, at 2, 7, 15, 30, and 240 days after irradiation (dpi). Sham-irradiated animals acted as controls.
RESULTS
Only an entrance dose of 800 Gy caused a significant increase in the thickness of both epidermal and dermal ear compartments seen from 15 to 30 dpi; the number of sebaceous glands was significantly reduced by 30 dpi. The numbers of apoptotic bodies and infiltrating leukocytes peaked between 15 and 30 dpi. Lymphatic vessels were prominently enlarged at 15 up to 240 dpi. Sarcomere lesions in striated muscle were observed after all doses, starting from 2 dpi; scar tissue within individual beam paths remained visible up to 240 dpi. Cartilage and blood vessel changes remained histologically inconspicuous.
CONCLUSIONS
Normal tissues such as skin, cartilage, and blood and lymphatic vessels are highly tolerant to MBI after entrance doses up to 400 Gy. The striated muscles appeared to be the most sensitive to MBI. Those findings should be taken into consideration in future micro-beam radiation therapy treatment schedules.
To analyze the effects of micro-beam irradiation (MBI) on the normal tissues of the mouse ear.
METHODS AND MATERIALS
Normal mouse ears are a unique model, which in addition to skin contain striated muscles, cartilage, blood and lymphatic vessels, and few hair follicles. This renders the mouse ear an excellent model for complex tissue studies. The ears of C57BL6 mice were exposed to MBI (50-μm-wide micro-beams, spaced 200 μm between centers) with peak entrance doses of 200, 400, or 800 Gy (at ultra-high dose rates). Tissue samples were examined histopathologically, with conventional light and electron microscopy, at 2, 7, 15, 30, and 240 days after irradiation (dpi). Sham-irradiated animals acted as controls.
RESULTS
Only an entrance dose of 800 Gy caused a significant increase in the thickness of both epidermal and dermal ear compartments seen from 15 to 30 dpi; the number of sebaceous glands was significantly reduced by 30 dpi. The numbers of apoptotic bodies and infiltrating leukocytes peaked between 15 and 30 dpi. Lymphatic vessels were prominently enlarged at 15 up to 240 dpi. Sarcomere lesions in striated muscle were observed after all doses, starting from 2 dpi; scar tissue within individual beam paths remained visible up to 240 dpi. Cartilage and blood vessel changes remained histologically inconspicuous.
CONCLUSIONS
Normal tissues such as skin, cartilage, and blood and lymphatic vessels are highly tolerant to MBI after entrance doses up to 400 Gy. The striated muscles appeared to be the most sensitive to MBI. Those findings should be taken into consideration in future micro-beam radiation therapy treatment schedules.
- Language
-
- English
- Open access status
- hybrid
- Identifiers
-
- DOI 10.1016/j.ijrobp.2018.02.007
- PMID 29559293
- Persistent URL
- https://sonar.ch/global/documents/278739
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