Quantitative evaluation of myofibroblast apoptosis during wound healing in rat palate after post-operative administration of basic fibroblast growth factor (bFGF).

OBJECTIVE: Excessive wound contraction apparently inhibits maxillary growth; thus, myofibroblast apoptosis needs to be accelerated in mucoperiosteal denudation after palatoplasty. The aim of this study was to evaluate myofibroblast apoptosis during wound healing in mucoperiosteal denudation of rat palates immediately after post-operative administration of basic fibroblast growth factor (bFGF). MATERIALS AND METHODS: A total of 100 male Wistar rats aged 20 days were divided into control, scar, sham and bFGF groups (n = 25 each). In the scar, sham and bFGF groups, mucoperiosteum was removed from the palate and fibrin glue was applied to the exposed bone surface immediately after surgery. In the bFGF group, 10 µL of 2 µg/µL bFGF solution was injected into the operated area beneath the fibrin glue. At 2, 5, 7, 14 and 28 days post-operatively, myofibroblast apoptosis during the wound healing process was investigated by double immunofluorescence staining. The apoptotic area of myofibroblasts was measured using image software. RESULTS: In the bFGF group, at 2 days, apoptosis of myofibroblasts in the lamina propria and submucosa was marked, as compared with the other three groups and apoptosis of myofibroblasts was scarcely seen at 5 days. At 5 and 7 days, the apoptotic area of myofibroblasts in the bFGF group was statistically significantly smaller when compared to the scar and sham groups. CONCLUSION: The results confirmed that bFGF injection immediately after surgery accelerated apoptosis of myofibroblasts in mucoperiosteal denudation of rats. This may reduce maxillary growth retardation due to excessive wound contraction.

Effects of basic fibroblast growth factor administration on vascular changes in wound healing of rat palates.

OBJECTIVE: The purpose of this study was to investigate the vascular changes induced by mucoperiosteal denudation of rat palate and to elucidate the effects of basic fibroblast growth factor (bFGF) administration on the palatal vascular network in wound healing. METHODS: A total of 117 male Wistar rats were used for the study on their 20th postnatal day. The animals were divided into three groups: a scar formation group, a basic fibroblast growth factor group, and a control group. The scar formation and basic fibroblast growth factor groups had lateral mucoperiosteum excised from the palate. In the basic fibroblast growth factor group, a solution of basic fibroblast growth factor was injected into the operated area 1 week after excision. At 6, 8, and 10 weeks postoperatively, palatal vascular changes were investigated by immunohistochemical staining and corrosion cast techniques. RESULTS: Throughout the experimental period, there were significantly fewer vessels in the scar formation group than in the control and basic fibroblast growth factor groups. In the basic fibroblast growth factor group, the elongation of new vessels and capillary proliferation proceeded, and after 10 weeks a highly organized vascular network was established. The scar formation group showed few Volkmann's canals that were shrunken or closed, whereas the basic fibroblast growth factor group evidenced Volkmann's canals with arterioles or venules, as seen in the control. CONCLUSIONS: The results suggested that injection of basic fibroblast growth factor into palatal wounds improves the vascular supply to the operated mucosa and underlying bone during and after palatal wound healing, which may contribute to tissue remodeling of the palate during growth.