Fig. 5

Accelerated tissue regeneration by incorporating 4-hexylresorcinol (4HR). a Silk and hydroxyapatite grafts were implanted into calvarial defects of rabbits. There was no bone regeneration at 8 weeks postoperation (Masson trichrome stain, original magnification ×100). b A silk fibroin, hydroxyapatite, and 4HR graft were implanted into the calvarial defect of a rabbit. There were numerous osteoid islands at 8 weeks postoperation (Masson trichrome stain, original magnification ×100). c A silk fibroin graft was implanted into the dermal pocket of a rat. There were many foreign body giant cells (asterisks) with silk fiber remnants at 12 weeks postoperation (HE stain, original magnification ×400). d A silk fibroin and 4HR graft were implanted into the dermal pocket of a rat. There were few foreign body giant cells (asterisks) at 12 weeks postoperation. Interestingly, capillary regenerations were prominent (arrow heads) (HE stain, original magnification ×400)