Background: Neuroendocrine effects of the prenatal radiation exposure from radioactive iodine in an event of nuclear power reactor accidents are a key issue in the field of radiation medicine and radiation safety because of a dramatic radiosensitivity of the developing organism.
Objective: Review of contemporary epidemiological, clinical and experimental data on neuroendocrine effects of prenatal exposure to 131I.
Object and methods: Search in the PubMed/MEDLINE and Google Scholar abstract databases, along with a manual search for the relevant data sources.
Results: Estimated absorbed doses of intrauterine thyroid irradiation from radioactive iodine were obtained based on ICRP Publication 88, both with estimates of effective radiation doses on embryo and fetus, and estimates of the brain equivalent doses upon exposure in utero. The latter ones are subject to updating. The evidence-based data has been presented regarding a radiation-associated reduction of head and chest circumference at birth, as well as a radiation-associated excess of goiter with large thyroid nodules, and possibly of thyroid cancer after a prenatal exposure to 131I radionuclides. Data on intrauterine brain damage are controversial, but most researchers share the view that there are cognitive and emotional-behavioral disorders due to prenatal and postnatal irradiation and psy- chosocial impacts. Incidence increase of non-cancerous endocrine disorders and degenerative vascular disease of retina was noted. An experimental model of intrauterine irradiation from 131I on Wistar rats was for the first time ever created, extrapolating the radioneuroembryological effects in rats to individuals prenatally exposed after the Chornobyl disaster. Late neuropsychiatric and endocrine effects may be resulted from the relatively short-term impact of ionizing radiation at a level previously been considered safe. The necessity of neuropsychiatric and endocrinological monitoring of individuals exposed prenatally to ionizing radiation after the Chornobyl catastrophe throughout their life is substantiated. Experimental animal studies are a key direction in the further research of radiation effects, especially associated with low radiation doses. Further experimental and clinical neuroradiobio- logical studies aimed at exploration of the effect of ionizing radiation on hippocampal neurogenesis are most rele- vant nowadays.
Peredumova. Ney̆roendokrynni efekty prenatal'nogo oprominennia radioaktyvnym y̆odom pry avariiakh na iader- nykh reaktorakh ie odnym z kliuchovykh pytan' radiatsiy̆noï medytsyny i radiatsiy̆noï bezpeky cherez vykliuchnu radio- chutlyvist' organizmu, shcho rozvyvaiet'sia.Meta roboty. Proanalizuvaty suchasni epidemiologichni, klinichni ta eksperymental'ni dani stosovno ney̆roendok- rynnykh efektiv prenatal'nogo oprominennia 131I.Ob’iekt i metody doslidzhennia. Poshuk u referatyvniy̆ medyko-biologichniy̆ bazi danykh PubMed/MEDLINE, Google Scholar ta ruchnyy̆ poshuk vidpovidnykh dzherel informatsiï.Rezul'taty. Otrymano otsinky poglynutykh doz vnutrishn'outrobnogo oprominennia shchytopodibnoï zalozy radioak- tyvnym y̆odom na osnovi Publikatsiï 88 MKRZ, otsinky efektyvnykh doz oprominennia embriona i ploda, a takozh otsinky ekvivalentnykh doz na golovnyy̆ mozok pry oprominenni in utero, iaki potrebuiut' utochnennia. Predstavle- no dokazovi dani shchodo radiatsiy̆no asotsiy̆ovanogo zmenshennia okruzhnosti golovy i grudnoï klityny pry narod- zhenni, a takozh shchodo radiatsiy̆no asotsiy̆ovanogo ekstsesu velykovuzlovogo zobu ta, mozhlyvo, raku shchytopodibnoï zalozy pislia prenatal'nogo oprominennia radionuklidom 131I. Dani shchodo vnutrishn'outrobnogo urazhennia golov- nogo mozku superechlyvi, ale bil'shist' doslidnykiv podiliaie tochku zoru pro naiavnist' kognityvnykh i emotsiy̆no-po- vedinkovykh rozladiv vnaslidok pre- i postnatal'nogo oprominennia i psykhosotsial'nykh prychyn. Vidmicheno zros- tannia nerakovykh endokrynnykh zakhvoriuvan' ta sudynno-degeneratyvnoï patologiï sitkivky oka. Vpershe stvore- no eksperymental'nu model' vnutrishn'outrobnogo oprominennia 131I shchuriv Vistar, iaka ekstrapoliuie radioney̆ro- embriologichni efekty u shchuriv na osib, vnutrishn'outrobno oprominenykh vnaslidok Chornobyl's'koï katastrofy. Viddaleni ney̆ropsykhiatrychni ta endokrynni efekty mozhut' buty zumovleni vidnosno korotkochasnym vplyvom ionizuiuchogo vyprominiuvannia, riven' iakogo ranishe vvazhavsia bezpechnym. Obґruntovano neobkhidnist' ney̆rop- sykhiatrychnogo ta endokrynologichnogo monitoryngu za vnutrishn'outrobno oprominenymy vnaslidok Chorno- byl's'koï katastrofy osobamy protiagom us'ogo ïkhn'ogo zhyttia. Kliuchovym napriamkom u podal'shomu doslidzhenni radiatsiy̆nykh efektiv, osoblyvo pov’iazanymy z malymy dozamy radiatsiï, ie eksperymental'ni doslidzhennia na tva- rynakh. Nay̆bil'sh aktual'nymy nyni ie podal'shi eksperymental'no-klinichni ney̆roradiobiologichni doslidzhennnia spriamovani na vyvchennia vplyvu ionizuiuchogo vyprominiuvannia na gipokampal'nyy̆ ney̆rogenez.
Keywords: 131І; Chornobyl disaster; late endocrine and neuropsychiatric effects; pathogenesis; prenatal irradiation.
K. M. Loganovsky, V. V. Talko, O. V. Kaminskyi, D. E. Afanasyev, S. V. Masiuk, T. K. Loganovskaya, G. Y. Lavrenchuk.