Ionizing radiation effects on the secretory-stage ameloblasts and enamel organic extracellular matrix.
This study assessed the effects of high doses of ionizing radiation on eruption rate, odontogenic region morphology, secretory-stage ameloblasts, and enamel organic extracellular matrix (EOECM) of rat maxillary incisors. For the study, 30 male rats were divided into three experimental groups: control (non-irradiated), irradiated by 15 Gy, and irradiated by 25 Gy. Irradiated groups received a single dose of 15 or 25 Gy of X-rays in the head and neck region. The maxillary incisor eruption rate was measured. Sections of 5-µm thickness of the maxillary incisor odontogenic regions were evaluated using bright field light microscopy. Ultrathin sections of secretory ameloblasts and their EOECM were analyzed by transmission electron microscopy (TEM). Irradiated groups showed significantly diminished eruption rate values at the 4th and at the 6th day after irradiation. Reduced optical retardation values were observed in the irradiated groups. The odontogenic region of maxillary incisors from irradiated rats exhibited altered and poorly organized preameloblasts. TEM showed degeneration areas in the secretory-stage EOECM and several autophagosomes in the secretory ameloblasts from irradiated animals. In conclusion, high radiation doses delay eruption and induce disturbances in secretory ameloblasts and EOECM of rat maxillary incisors. These findings may be associated with structural defects of mature enamel.
Área de Radiologia Odontológica, Departamento de Clinica e Odontologia Preventiva, Universidade Federal de Pernambuco, Avenida Prof. Moraes Rego, 1235, Cidade Universitária, CEP 50670-901, Recife, PE, Brazil, flavia.ramosperez@ufpe.br.
Flávia Maria
FM
de Moraes Ramos-Perez
Alexandre Ribeiro
AR
do Espírito Santo
Danyel Elias
DE
da Cruz Perez
Pedro Duarte
PD
Novaes
Frab Norberto
FN
Bóscolo
Sérgio Roberto Peres
SR
Line
Solange Maria
SM
de Almeida
D000565:Ameloblasts / Q000378:metabolism* / Q000528:radiation effects*; D000818:Animals; D004658:Enamel Organ / Q000166:cytology*; D005109:Extracellular Matrix / Q000528:radiation effects*; D007180:Incisor / Q000166:cytology; D008297:Male; D051381:Rats