Radiation effects on senescence accelerated mouse (SAM P/8)

There is controversy as to whether or not aging is accelerated by irradiation. We discuss the effects of irradiation on SAM P/8. Several morphometric age-related changes of the cerebral capillaries have been reported, such as an increase in the thickness of basement membrane, decrease in the number of endothelial cell mitochondria and loss of endothelial cells. In the present study, the mitochondrial density of endothelial cells was not apparently affected by irradiation, but the wall thickness index of cerebral capillaries in the irradiation group of SAM P/8 was significantly higher than that in the control group. It is suggested that an increase of basement membrane in the cerebral capillaries caused by irradiation altered the vascular permeability, thereby accelerating aging. (author)