Effect of X-rays on selenium content in rat jaws.

It is known that X-radiation of the growing jaws results in impaired dental development. We investigated the role of selenium (Se) in radiation-induced dental growth retardation. The heads of 8-day-old female rats were irradiated with a single dose of 9.6 Gy of X-rays. Another group of animals was irradiated under the same conditions but, for radioprotective purposes, were also in deep hypothermia during radiation exposure. Nonirradiated animals served as controls. The Se content in the upper and lower jaws was analyzed by hydride generation atomic absorption spectrophotometry. In the upper jaws of the animals exposed to irradiation, the Se concentration was significantly lower than in those irradiated under conditions of hypothermia (p < 0.05), although both groups showed no significant difference in Se concentration when compared to nonirradiated controls. In the lower jaws, the concentration of Se was significantly reduced in the irradiated group when compared with controls and the rats irradiated under conditions of hypothermia (p < 0.05). There was no significant difference in Se concentration between rats irradiated under conditions of hypothermia and nonirradiated controls. There was no significant change in Se concentration in the jaws of the rats protected by hypothermia during radiation exposure compared with nonirradiated controls. Although Se loss in the irradiated bone could be prevented by hypothermia, we could not prove that Se loss per se is the cause of growth retardation nor that its retention has a radioprotective effect.