Volumetric modifications of X-irradiated keratinocytes

The number of epithelial cells per unit volume of tissue (NV) and the relative volume (VV) occupied by the spinous and basal layers of X-irradiated and non-irradiated rat-tail epidermis were studied using techniques of stereologic cytology. By a simple calculation, the absolute volumes of basal and spinous keratinocytes were determined in irradiated (and in non-irradiated, control) epidermis, 24, 48, 72 and 96 h after exposure to a single dose of 16 Krads. During this post-irradiation period, the absolute volumetric values of both basal and spinous keratinocytes increased gradually, reaching a three-fold increase 96 h after irradiation. At the same time, the relative volume of the spinous layer increased from 58% to 75% of the total epidermis, whereas the volume fraction occupied by the basal layer decreased from 20% to 16%. These findings support previous evidence that lethally and sublethally damaged keratinocytes are capable of a metabolic effort resulting in a cell hypertrophy which in some circumstances could lead to repair and recovery from radiation damage.