Evaluation of the efficacy of electrospun gelatin/polycaprolactone nanofiber membranes in repairing beagle dog buccal mucosa defects and a comparative study with acellular dermal matrix.

Objective: This study aimed to evaluate the efficacy of electrospun gelatin/polycaprolactone (GT/PCL) nanofibrous membranes in repairing full-thickness buccal mucosal defects in beagle dogs, compared with clinically used acellular dermal matrix (ADM) membranes, thereby providing experimental evidence for clinical translation. Methods: First, a stable, full-thickness buccal mucosal defect model (2.5 cm × 1.5 cm) was established in beagle dogs using individually designed and fitted palatal protectors. A stepwise bilateral self-paired design was then adopted. In Part I, GT/PCL membranes were implanted into one side of the defect (n = 3), with the contralateral untreated side serving as the control. Macroscopic observations were performed at postoperative days 7 and 14. At day 14, histological assessments-including hematoxylin-eosin (HE) staining, Masson's trichrome staining, immunohistochemical staining for CD34 and α-smooth muscle actin (α-SMA), along with hydroxyproline (Hyp) quantification-were used to assess wound shrinkage, epithelial regeneration, collagen formation, angiogenesis, and myofibroblast-associated remodeling. In Part II, GT/PCL and ADM membranes were separately implanted into bilateral defects in an additional 9 beagle dogs, which were equally allocated to day 7, day 14, and day 28 endpoint subgroups (n = 3 per time point), followed by comparative analyses of the same outcome measures. Results: The individually tailored palatal protectors effectively shielded the implanted materials. Compared with the control, GT/PCL membranes significantly accelerated wound healing, evidenced by a lower wound shrinkage rate (P < 0.05), thicker regenerated epithelium (P < 0.05), higher collagen volume fraction and Hyp content (P < 0.05), increased neovascularization (P < 0.05), and reduced α-SMA expression (P < 0.05). In comparison with ADM, GT/PCL membranes promoted significantly greater early epithelial ingrowth and higher collagen-related indices at days 7 and 14 (P < 0.05). However, wound shrinkage rate, neovascularization (CD34-positive vessels), and α-SMA expression did not differ significantly between the two groups (P > 0.05). By day 28, most outcomes were comparable between GT/PCL and ADM. Conclusion: GT/PCL electrospun nanofibrous membranes exhibit good biocompatibility and effectively support repair of buccal mucosal defects. Compared with spontaneous healing, GT/PCL improved early wound repair. Compared with ADM, GT/PCL promoted earlier epithelial ingrowth and collagen-related matrix deposition during the early phase of healing. However, because most differences between GT/PCL and ADM were attenuated by postoperative day 28, the present findings support an early reparative advantage of GT/PCL rather than definitive long-term superiority over ADM.