Induction of chronic skin changes in intraperitoneally hematoporphyrin-injected mice with metal halide lamp irradiation.

Abstract

AbstractTo induce chronic skin changes simulating human porphyria, mice which had been injected intraperitoneally with hematoporphyrin dihydrochloride were exposed to metal halide lamps. Clinical and histopathological findings in the mice were observed. Clinically, erythema, edema, erosion, necrosis and crust formation were initially seen in all of the mice treated. Hypertrophy of the skin, scarring, and deformities of the ear lobes followed gradually. Histopathological findings in these skin changes were mainly seen in the dermis and included infiltration of lymphocytes, proliferation of mast cells, dilatation and hyperemia of blood vessels in the upper dermis, and swelling and proliferation of connective tissues. PAS positive materials were deposited in the dermo‐epidermal junction and around the small blood vessels in the upper dermis. Using the direct immunofluorescent technique, the deposition of immunoglobulin G (IgG) was confirmed in the same areas, and some deposition of IgM, IgA and C3 was also observed. These findings are similar to those seen in patients with erythropoietic protoporphyria and porphyria cutanea tarda.