Localization of small leucine‐rich proteoglycans and transforming growth factor‐β in human oral mucosal wound healing

Wound healing in oral mucosa is fast and results in little scar formation as compared with skin. The biological mechanisms underlying this property are poorly understood but may provide valuable information about the factors that promote wound regeneration. Small leucine‐rich proteoglycans (SLRPs) decorin, biglycan, fibromodulin and lumican are extracellular matrix molecules that regulate collagen fibrillogenesis, inhibit transforming growth factor‐β (TGF‐β) activity and reduce scarring. In the present study, we analyzed accumulation of SLRPs and TGF‐β during non‐scarring human oral mucosal wound healing. Biopsies were collected from healthy volunteers from unwounded tissue and from standardized experimental wounds 3–60 days postwounding. Localization of SLRPs, TGF‐β1 and TGF‐β3 was analyzed by immunohistochemical staining and quantitated by image analysis. Double immunostaining was used to study localization of SLRPs or active TGF‐β in distinct cells. Decorin, biglycan, fibromodulin, and TGF‐β isoforms showed significantly increased accumulation in the wound extracellular matrix and distinct wound cells while the abundance of lumican in the extracellular matrix was strongly reduced during wound healing. Localization and abundance of fibromodulin, lumican, and TGF‐β isoforms was also spatiotemporally regulated in the wound epithelium. The findings suggest that SLRPs regulate wound reepithelialization and connective tissue regeneration during oral mucosal wound healing.