Regenerative Capacity of Eggshell Membrane in Management of Critical-Sized Bone Defect: An Experimental Study

Objectives: This study aimed to evaluate the regenerative potential of eggshell membrane (ESM) in critical-sized bone defects (CSBD) and its synergistic effect with xenograft bone through histological and histomorphometric analysis. Materials and Methods: Thirty-two male Wistar rats were used, each receiving bilateral femoral CSBDs (2 mm diameter/depth). Defects were divided into: Group I (Control): Filled with xenograft alone (n=32 defects). Group II (Test): Filled with ESM-xenograft composite (n=32 defects). Rats were sacrificed at 4- and 8-weeks post-operation. Bone regeneration was assessed via H&E and Masson’s trichrome staining, with histomorphometric analysis using ImageJ software. Results: The Test group showed significantly higher bone regeneration (27.7 ± 1.57% at 4 weeks; 86.53 ± 3.81% at 8 weeks) compared to the Control group (15.44 ± 2.12% and 55.98 ± 2.53%, respectively; p<0.001). Collagen deposition was also greater in the Test group (54.79 ± 1.52% vs. 24.48 ± 1.73% at 4 weeks). Histologically, the Test group exhibited mature lamellar bone by 8 weeks, while the Control group showed slower maturation. Conclusions: ESM enhances bone regeneration synergistically with xenograft, offering a promising, cost-effective biomaterial for CSBD management. Unstructured Abstract: This experimental study assessed eggshell membrane (ESM) combined with xenograft for critical-sized bone defect (CSBD) repair in 32 rats. CSBDs were created bilaterally in femurs, treated with xenograft alone (Control) or ESM-xenograft (Test), and evaluated histologically at 4/8 weeks. Results demonstrated superior bone regeneration and collagen synthesis in the Test group (p<0.001), with 86.53% new bone formation by 8 weeks versus 55.98% in Controls. ESM’s osteoconductive properties suggest clinical potential for bone defect therapies.