Increased Activity of Skin Surface Dnase I After β-Irradiation Injury or Clipping of Guinea Pig Hair

Abstract

Small amounts of DNase I can be washed with saline from the guinea pig skin surface immediately after close clipping of hair. Within 24 hours after this relatively mild trauma, there was a 10–20 fold increase in skin surface DNase I activity. Two to ten days after 3000 rep β-irradiation of the closely clipped skin, both the nonirradiated and irradiated areas had similar increased levels of skin surface DNase I. By the 2nd week or longer, however, the nonirradiated areas had returned toward the low initial values, whereas the irradiated areas (beginning regeneration and repair) maintained a high activity. This increment was not the result of a slow accumulation of enzyme over many days, for after washing the irradiated skin surface free of DNase I at these later intervals there was a return to the same high enzyme level within 24 hours. The biological significance and physiologic mechanisms most, likely to account for this increase in skin surface DNase I are discussed.