Collagen V nasal tolerance in experimental model of systemic sclerosis

Our aim was to study skin remodeling and autoantibody production in an experimental model of scleroderma (SSc), following nasal tolerance with human type V collagen (Col V). Female New Zealand rabbits (n = 12) were immunized with two doses of 1 mg/ml of Col V in complete Freund's adjuvant and additional two boosters in incomplete Freund's adjuvant to induce SSc. After 150 days, half of these immunized rabbits were submitted to type V collagen-induced tolerance receiving a daily nasal administration of 25 mug of Col V. Control animals (n = 6) were only submitted to type V collagen-induced tolerance. Serial skin biopsies were performed on days 0, 150 and 210, and stained with H&E, Masson's trichrome and Picrosirius for morphological and morphometric analysis. Types I, III and V collagen were identified by immunofluorescence. The animals' serum samples were collected to determine anti types I, III, IV and V collagen and antinuclear antibodies (ANA). Skin biopsies from immunized animals confirmed SSc morphology as previously described, such as progressive decrease of papillary dermis, appendages atrophy, increased type I, III and V collagen deposition. Rabbits with Col V-induced nasal tolerance showed reduction of skin involvement, with significant decrease of collagen amount. Humoral immune response did not change with nasal tolerance. Collagen V nasal tolerance promotes regression of skin remodeling process in an experimental model of SSc. We suggest that nasal tolerance with type V collagen can be a promising therapeutic option to treat scleroderma patients.