Strabismus is a significant cause of a decrease in the functional capabilities of the organ of vision, additionally, it leads to the deteriorating quality of life. Orbital factors and nervous system changes may play an important role in strabismus pathogenesis. There are few reports on binocular vision disorders in radiation-exposed persons.Functions of the external eyeball muscles might be disturbed based on the changed coordination process of subcortical nerve structures and due to altered metabolism. A carefully conducted research is necessary to clarify the possible pathogenesis of binocular vision disorders in radiation-exposed persons.
Objective: to assess the peculiarities of the development of strabismus and binocular vision disorders in people who were exposed to ionizing radiation in utero; to investigate the changes in distribution and appearance of myosin, dystrophin, and collagen IV between non-irradiated persons with normal binocular vision and patients with strabismus.
Materials and methods: 583 persons, irradiated in utero because of the Chornobyl disaster were examined (at the time of examination average age was 11.3 ± 0.1 years). The control group - 808 people - Kyiv residents. Overall, 15 non-irradiated eyeball muscle samples were examined. 10 were from strabismus patients and 5 were controls. To evaluate morphological structure haematoxylin and eosin staining were used. For the detection of myosin, dystrophin, and collagen IV biotin-avidin (IMH) immunohistochemistry method was performed. Semi-quantitative grading method was used for the evaluation of immunoreactive structure appearance and local distribution.
Results: An increased frequency of divergent strabismus (p = 0.04190) and heterophoria (p = 0.002603) was found in the group exposed to prenatal (fetal) radiation because of the Chornobyl disaster compared to the control group. The relative risk of heterophoria was 5.08 (1.42 - 18.13). A decrease in dystrophin, myosin, and collagen IV positive structures was observed in non-irradiated strabismus-affected eyeball muscles compared to the control group.
Conclusions: Detected changes indicate an increased probability in the development of strabismus in persons who had been exposed to fetal radiation. Non-irradiated strabismus-affected eyeball muscles are characterized by diminished myosin, dystrophin, and collagen IV immunohistochemical structures. Additionally, determined qualitative morphological changes in skeletal striated muscle fibers lead to the changed structural organization, indicating possible muscular dystrophy. Thereby, the presence of dystrophic processes in the eyeball muscles may play a significant role in the morphopatogenesis of strabismus. Further morphological studies are necessary to clarify the development of binocular vision disorder and the methods of their correction. These studies would be especially important to populations that were exposed to radiation.
Kosookist' - vagoma prychyna znyzhennia funktsional'nykh mozhlyvosteĭ organa zoru i pogirshennia iakosti zhyttiapatsiientiv. Mozhlyvyĭ mekhanizm patogenezu kosookosti vkliuchaie orbital'ni faktory i zminy nervovoï systemy.Povidomlennia pro porushennia binokuliarnogo zoru u radiatsiĭno oprominenykh osib nechyslenni. Funktsiï zovnishnikh m’iaziv ochnogo iabluka mozhut' buty porusheni vnaslidok zminy koordynatsiĭnogo protsesu pidkirkovykh nervovykh struktur i vnaslidok zminy metabolizmu. Dlia z’iasuvannia mozhlyvogo patogenezu rozladiv binokuliarnogo zoru u osib, iaki zaznaly oprominennia, neobkhidni retel'ni doslidzhennia.Meta: otsinyty osoblyvosti rozvytku kosookosti ta porushen' binokuliarnogo zoru v osib, iaki zaznaly vplyvu ionizuiuchogo vyprominiuvannia u vnutrishn'outrobnomu periodi; doslidyty zminy u rozpodili ta poiavi miozynu, dystrofinu ta kolagenu IV mizh neoprominenymy osobamy z binokuliarnym zorom ta osobamy, shcho strazhdaiut' na kosookist'.Materialy ta metody. Obstezheno 583 osoby, iaki otrymaly vnutrishn'outrobne oprominennia vnaslidok Chornobyl's'koï katastrofy; ïkhniĭ seredniĭ vik na moment obstezhennia stanovyv (11,3 ± 0,1) rokiv. Grupu porivniannia sklaly 808 osib, meshkantsiv m. Kyieva. Paralel'no bulo doslidzheno 15 zrazkiv m’iaziv ochnogo iabluka neoprominenykh osib, z iakykh 10 osib strazhdaly na kosookist' i 5 nalezhaly do kontrol'noï grupy. Dlia otsinky morfologichnoï struktury vykorystovuvaly zabarvlennia gematoksylin-eozynom. Dlia vyiavlennia miozynu, dystrofinu ta kolagenu IV zactosuvaly biotyn-avidynovyĭ (biotin-avidin (IMH)) imunogistokhimichnyĭ metod. Dlia otsinky zovnishn'ogo vygliadu imunoreaktyvnykh struktur ta ïkh lokal'nogo rozpodilu vykorystovuvaly napivkil'kisnyĭ metod graduiuvannia.Rezul'taty. U grupi vnutrishn'outrobno oprominenykh vnaslidok Chornobyl's'koï katastrofy osib vyiavleno pidvyshchenu, u zistavlenni z grupoiu porivniannia, chastotu rozbizhnoï kosookosti (r = 0,04190) ta geteroforiï (r = 0,002603). Vidnosnyĭ ryzyk geteroforiï sklav 5,08 (1,42–18,13). U neoprominenykh m’iazakh ochnogo iabluka, urazhenykh kosookistiu, sposterigalosia znyzhennia rivnia dystrofinu, miozynu ta kolagenu IV pozytyvnykh struktur porivniano z kontrol'noiu grupoiu. Vysnovky. Vyiavleni zminy vkazuiut' na pidvyshchenu ĭmovirnist' rozvytku kosookosti v osib, iaki zaznaly vnutrishn'outrobnogo oprominennia. M’iazy ochnogo iabluka, urazheni kosookistiu u neoprominenykh osib, kharakteryzuiut'sia znyzhenniam imunogistokhimichnykh struktur miozynu, dystrofinu ta kolagenu IV. Iakisni morfologichni zminy vskeletnykh poperechnosmugastykh m’iazovykh voloknakh, zminy strukturnoï organizatsiï, vkazuiut' na mozhlyvu m’iazovu dystrofiiu. Takym chynom, naiavnist' dystrofichnykh protsesiv u m’iazakh ochnogo iabluka mozhe vidigravaty istotnu rol' u morfopatogenezi kosookosti. Dlia utochnennia rozvytku porushen' binokuliarnogo zoru ta metodiv ïkh korektsiï neobkhidni podal'shi morfologichni doslidzhennia. Tsi doslidzhennia budut' osoblyvo vazhlyvi dlia naselennia, iake zaznalo vplyvu radiatsiï.
Keywords: eyeball muscles; immunohistochemical studies; ionizing radiation; irradiated in utero; pathogenesis; strabismus.
P. Fedirko, M. Pilmane, T. F. Babenko, V. Konopecka.