{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T08:20:32Z","timestamp":1787818832611,"version":"build-2784847793"},"reference-count":18,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T00:00:00Z","timestamp":1787788800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002241","name":"Japan Science and Technology Agency","doi-asserted-by":"publisher","award":["JPMJFR211E"],"award-info":[{"award-number":["JPMJFR211E"]}],"id":[{"id":"10.13039\/501100002241","id-type":"DOI","asserted-by":"publisher"}]},{"award":["JPMJFR211E"],"award-info":[{"award-number":["JPMJFR211E"]}],"id":[{"id":"https:\/\/ror.org\/00097mb19","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Int. J. Mol. Sci.","IJMS"],"abstract":"<jats:p>Early-life ionizing radiation exposure may induce molecular responses without changes in birth outcomes. We examined whether in utero exposure to 0.2 Gy X-rays affects mitochondrial DNA copy number (mtDNAcn) and an index estimating the proportion of mitochondrial DNA (mtDNA) molecules amplifiable across a defined long region. Pregnant mice received sham irradiation or exposure on embryonic day 8 (E8) or 15 (E15). Offspring brain, heart, and liver were examined at birth, with litter means used as experimental units. Litter size and neonatal body weight showed no group differences. In organ-wise comparisons, brain mtDNAcn was higher after E8 and E15 exposure, heart mtDNAcn was higher after E15 exposure, and liver mtDNAcn showed no statistically detectable difference. Mixed-effects analysis supported an organ-dependent pattern of mtDNAcn responses, although direct E8-versus-E15 comparisons were not significant within any organ. The estimated proportion of long-fragment-amplifiable mtDNA was lower in the brain after E15 exposure in the organ-wise analysis, but mixed-effects analysis did not support organ- or gestational-stage-dependent patterns in this measure. Thus, in utero X-ray exposure produced organ-dependent mtDNAcn responses at birth but no demonstrable gestational-stage-specific response within individual organs.<\/jats:p>","DOI":"10.3390\/ijms27177671","type":"journal-article","created":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T08:02:27Z","timestamp":1787817747000},"page":"7671","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Organ-Specific Mitochondrial DNA Copy Number Responses in Neonatal Mice Following in Utero Irradiation"],"prefix":"10.3390","volume":"27","author":[{"given":"Haruka","family":"Kubo","sequence":"first","affiliation":[{"name":"Division of Health Sciences, Graduate School of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-4187-1993","authenticated-orcid":false,"given":"Ryosuke","family":"Seino","sequence":"additional","affiliation":[{"name":"Department of Radiological Technology, Faculty of Health Sciences, Hokkaido University of Science, Sapporo 006-8585, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6264-187X","authenticated-orcid":false,"given":"Hisanori","family":"Fukunaga","sequence":"additional","affiliation":[{"name":"Department of Biomedical Science and Engineering, Faculty of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan"},{"name":"Center for Environmental and Health Sciences, Hokkaido University, Sapporo 060-0812, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"607","DOI":"10.1016\/j.freeradbiomed.2013.07.024","article-title":"Effects of Ionizing Radiation on Mitochondria","volume":"65","author":"Kam","year":"2013","journal-title":"Free Radic. 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