Release of intracellular enzymes from cutaneous cells after non-necrotizing damage by ultraviolet light

Summary Experimental blisters were produced with suction on normal human skin and simultaneously on skin inflamed after exposure to middle wave ultraviolet light. Total proteins and marker enzymes for the plasma membrane, cytosol, lysosomes, peroxisomes, mitochondria, and microsomes were assayed in the blister fluid. In blisters on erythematous skin, a large increase of lactate dehydrogenase from cytosol was noted. A small increase of the plasma membrane marker phosphodiesterase I and some increase of -mannosidase from lysosomes was also found. No significant increase in total proteins or in the markers for peroxisomes was observed, whereas mitochondrial and microsomal marker enzymes were not detectable.It is concluded that cutaneous cells to some extent may lose intracellular enzymes without visible signs of irreversible damage (necrosis), but that an UVB-induced injury/regeneration cycle probably explains the enzyme release.