Development of an in vitro model for radiation-induced effects on oral keratinocytes

Linear regression analysis survival curve. The dose of 50% and 90% CFE was 1.4 and 3.7Gy, respectively, from Eq. (2).

The colony forming and oral keratinocyte shape after X-ray irradiation. Colony formation decreased as radiation dose increased. The number of oral mucosa keratinocytes decreased in number as the radiation dose increased. Cell morphology changed from a smooth and oval appearance to a stretched and irregular shape, indicative of cellular degenerative changes.

The histological change of EVPOMEs after ionizing radiation. At 0Gy, the EVPOME appeared healthy with well-aligned cells along the basement membrane. At 8Gy, oral mucosa keratinocytes were aberrant in alignment and faint nuclear staining of the basal cells was seen. The basal cell had pyknoic nuclei (HE stain, ×200).

The result of Ki-67 immunohistochemistry. At 0Gy, Ki-67 positive cells are mainly seen within the basal layer of cells. At 8Gy, the number of positive cells dramatically decreased and they were scarce (×200).

PI of Ki-67 positive basal keratinocytes. PI decreased as the radiation dose increased. Significant differences were seen at 1, 3 and 8Gy (p<0.05). The x-axis indicates the radiation dose and the y-axis the PI. Each value represents mean±SEM.

Result of the MTT cell viability assay. Cell viability decreased dose-dependently. Difference was statistically significant at 8Gy (p<0.05). The x-axis shows the radiation dose, the y-axis shows the ratio of the viability. Each value is mean±SEM.