title: Prevention of photocarcinogenesis and UV-induced immunosuppression in mice by topical tannic acid.
abstract: Topical application of tannic acid, a phenolic antioxidant derived from plants, was found to inhibit the cutaneous carcinogenesis and the immunosuppression induced by ultraviolet B (UVB) irradiation with no visible toxicity. BALB/cAnNTacfBR mice were treated with 200 micrograms of tannic acid three times weekly for two weeks before UV treatments began and throughout the experiment. UVB irradiation consisted of five 30-minute exposures per week to banks of six FS40 Westinghouse sunlamps. In the photocarcinogenesis study, mice received a total dose of approximately 1.09 x 10(6) J/m2. Skin cancer incidence in UV-irradiated mice was 75% at 26 weeks after the first UV exposure; tannic acid reduced this to 42%. Immunosuppression induced by UVB irradiation normally prevents the host from rejecting antigenic syngeneic UV-induced tumors. Immunosuppression in these experiments was measured by a passive transfer assay. Tumor challenges grew to an average of 88 +/- 20, 36 +/- 11, and 20 +/- 8 mm2 in naive recipients of splenocytes from UVB-irradiated mice, nonirradiated control mice, and UVB-irradiated mice treated with tannic acid, respectively. Thus topical tannic acid treatment prevented the transfer of enhanced tumor susceptibility with splenocytes from UVB-irradiated mice.
mesh_terms: D000287:Administration, Topical; D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced / Q000276:immunology / Q000517:prevention & control; D046508:Culture Techniques; D005260:Female; D047348:Hydrolyzable Tannins / Q000008:administration & dosage* / Q000627:therapeutic use; D007108:Immune Tolerance / Q000187:drug effects / Q000528:radiation effects; D016130:Immunophenotyping; D007165:Immunosuppression Therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D009381:Neoplasms, Radiation-Induced / Q000276:immunology / Q000517:prevention & control*; D012867:Skin / Q000473:pathology / Q000528:radiation effects*; D012878:Skin Neoplasms / Q000276:immunology / Q000517:prevention & control*; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000166:cytology / Q000276:immunology; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D047348:Hydrolyzable Tannins