Accelerating Effects of Silk Fibroin on Wound Healing in Hairless Descendants of Mexican Hairless Dogs

We examined the safety of silk fibroin in the subcutaneous tissues. In addition, we macroscopically and histopathologically evaluated its healing effect on the full-thickness wounds in hairless dogs. We prepared 3 types of matrices including amorphous silk fibroin films, and a-and â-type silk fibroin p owder. N o toxicity was fo und in the sites injected with silk fibroin so lutions. M acroscopically, silk f ibroin films had accelerating effects on wo und repair, as compared with occlusive d ressings (dried porcine skin a nd hydrocolloid dressings). Histopathological ex aminations re vealed that sil k fibroin films facilitate reepithelialization and the formation of granulation tissues, collagens and elastic fibers. The sites treated wi th t he a-type si lk f ibroin powder were faster i n wo und repair than those t reated with t he â-type silk f ibroin powder. The a-type silk fibroin p owder a bsorbed excessive exudate. M icroscopically, there are epidermal and dermal regeneration in the sites treated with t he a-type silk fibroin powder. These results show that sil k fibroin is inert in biological t issues, ind icating excellent b iocompatibility. Silk fibroin films facilitate r eepithelialization, remodeling of connective tissues and col lagenization. The a- type f ibroin powder is a w ound dressing that regulates excessive exudate f rom the wound and provides a proper m oist environment. These results suggest tha t sil k fibroin is a useful dressing material i n veterinary clinical medicine.