Spatial and temporal expression of basic fibroblast growth factor protein during wound healing of rat skin

Background Basic fibroblast growth factor (bFGF) stimulates the mitogenesis of various cells and plays a key part in wound healing. Objectives To determine the spatial and temporal expression of bFGF protein during wound healing after burning of rat skin. Methods Immunohistochemical methods were used. Results The immunostaining for bFGF in the normal epidermis was faint and s poradic in the basal cell layer. However, significant staining for bFGF was found in four locations: regenerated epidermis, a band-like zone near the regenerated epidermis, renewed capillaries, and cells infiltrating into the granulation tissue at the inflammatory to proliferative stages after the b urn. The intensity of immunostaining of regenerated epidermis, the band-lik e zone and renewed capillaries was maximal during the proliferative stage a nd decreased to normal levels or disappeared simultaneously with wound clos ure. Immunopositive macrophage-like cell numbers in the granulation tissue increased during the proliferative stage and promptly decreased after wound closure, but such cells were only poorly visible in the scar tissue until 42 days postburn. Conclusions bFGF may affect the proliferation, differentiation and migratio n of regenerated keratinocytes and the recruitment of inflammatory cells, a s well as neovascularization in granulation tissue during wound healing. Ma crophages may play a pivotal role in cutaneous wound repair by producing bF GF not only during the inflammatory or proliferative stages but also during the remodelling stage.