Figure 3. Immunocytochemical analysis of p16 ^INK4 in kidneys of 3 month old Ku86^+/+ and Ku86^-/- mice.

Many senescent cells (brown stain) are present in kidneys of Ku86^-/- mice. p16^INK4 is higher in the renal medulla, where salt concentration normally is always high, than in the cortex, where the salt concentration is similar to that in peripheral blood. p16^INK4 level and staining pattern in kidneys of 3 month old Ku86^-/- mice are similar to those observed previously in 12 month old wild type mice [4].