Age-related local versus systemic early phase wound healing dynamics following free gingival graft harvest.

BACKGROUND

Free palatal gingival grafts (FGG) are commonly harvested during mucogingival procedures. The present study investigates age-related local and systemic early secondary wound healing outcomes, following FGG harvest in a rat model.

METHODS

A 4.2 mm diameter defect was created in the palate of 24 younger (2 m) and 24 older (6 m) Wistar male rats. They were divided according to experimental days 1-4. Values of complete blood count, chemistry analysis, and inflammatory biomarkers were assessed. Specimens were examined histologically.

RESULTS

Wound healing was similar between groups, with a significant de-epithelized surface reduction from day 1 to day 2 (p = 0.0007) and day 2 to day 3 (p = 0.002), without a significant difference between day 3 and day 4 (p = 0.4). Histological inflammation scores were consistently higher in younger individuals, suggesting a more pronounced local inflammatory response. Picrosirius red staining revealed more dynamic collagen fiber organization in the younger rats, with significant differences at days 2 (p = 0.01), 3 (p = 0.03), and 4 (p = 0.03). Age-related differences were noted regarding levels of WBC (white blood cells), RBC (red blood cells), HGB (hemoglobin), HCT (hematocrit), MCV (mean corpuscular volume), MCH (mean corpuscular hemoglobin), platelet counts, creatinine, SGPT (serum glutamic pyruvic transaminase), SGOT (serum glutamic-oxaloacetic transaminase), and AlkPhos. Younger rats displayed higher MCV, MCH, platelet counts, and a delayed rise in SGPT, creatinine, and AlkPhos over time, whereas older rats presented constantly higher WBC, RBC, HGB, HCT, and creatinine levels. Serum TNF-α levels were initially higher in the older rats but declined rapidly. In contrast, IL-6 peaked earlier and was higher in the older rats. IL-18 peaked earlier in the older (day 2) compared with the younger rats (day 3).

CONCLUSIONS

Local and systemic early events following surgery of the palatal mucosa revealed age-related differences. The older rats demonstrated in general a decreased local response vs. an increased systemic response.

PLAIN LANGUAGE SUMMARY: Free palatal gingival grafts are commonly harvested during mucogingival procedures around teeth and implants. The present study investigated age-related local and systemic early phase outcomes following palatal free gingival harvest with a 4.2 mm diameter punch in a rat model. Younger and older Wistar male rats were included and divided into four experimental groups according to experimental days 1-4. Systemic outcome parameters included complete blood count, chemistry analysis, and immunological parameters. Biopsies were examined for local histological-inflammatory outcome and collagen immunohistochemistry. Wound healing was similar between the older and younger groups. Local inflammation scores were consistently higher in younger rats. Collagen staining revealed more dynamic activity in the younger rats. The older group exhibited higher and more stable serologic levels of WBC, RBC, HGB, HCT, and creatinine. The younger group displayed higher serologic MCV, MCH, platelet counts, and a delayed rise in SGPT, creatinine, and AlkPhos over time. Serum TNF-α levels were initially higher in the older group but declined rapidly, IL-6 peaked higher in the older group and IL-18 peaked earlier in the older group. It can be concluded that local and systemic wound healing early events following surgery of the palatal mucosa reveal age-related differences. The older group demonstrated in general a decreased local response versus an increased systemic response.