Aplicação de proteínas toleradas por via subcutânea ou tópica melhora a cicatrização de feridas cutâneas em camundongos

Abstract

Skin wound healing depends on interactions between many types of cells that result in local inflammation and activation, migration and proliferation of keratinocytes, fibroblasts, endothelial cells and leukocytes. Through oral tolerance, an immunological phenomenon that occurs after protein intake, it is possible to inhibit the production of antibodies and reduce inflammation. Previous works have shown that an intraperitoneal injection of orallytolerated proteins plus adjuvant, minutes before skin injuries in mice, reduces inflammation and improves wound healing. Herein we evaluated whether two other routes of application - subcutaneous injection (s.c.) and topical application - of previously ingested proteins also improve wound healing. We used two different proteins: Zein that is a regular component of mice chow; and Ovalbumin that was added in the water offered to the mice for 3 consecutive days, before skin lesions. Two excisional lesions on the dorsal skin were performed in 8-week-old male C57Bl/6 mice with a 6 mm dermatological punch, under anesthesia. One s.c. application of the previously ingested proteins, in adjuvant, was made at the base of the tail, minutes before the lesions. Topical treatment with the previously ingested proteins, without adjuvant, was applied to the wounds for seven consecutive days. Non-tolerant control groups received treatment with the previously ingested proteins or vehicle. Wound healing was analyzed macroscopically and microscopically after staining with H&E, toluidine blue, Alcian Blue-Safranin, Masson's Trichrome, Picrosirus Red and Weigert's Resorcin-Fuchsin. The amount and distribution of leukocytes (CD45), macrophages (F4 / 80), T lymphocytes (CD3), myofibroblasts (α-SMA) and Vimentin was investigated in the wound bed by immunofluorescence. Macroscopic analyzes showed less inflammation and scarless healing in animals that received application of the tolerated proteins. Microscopic analyzes on day 7 after the injuries showed reduced inflammatory infiltrate in the groups that received application of tolerated proteins. At 40 and 60 days after the injuries, the organization of the extracellular matrix in neodermis of the groups that received application of tolerated proteins was more similar to that of intact skin. We conclude that the application of tolerated proteins decreases inflammation and improves the healing of skin lesions regardless of the route of application.