Bone healing evaluation of nanofibrous composite scaffolds in rat calvarial defects: a comparative study

We studied the in vivo performance of scaffolds consisting of nanofibrous poly(L-lactic acid) (P) and blend of poly(L-lactic acid/gelatin) (PG) prepared by electrospinning and further composited them with hydroxyapatite (HA) via alternate soaking method, to get poly(L-lactic acid)/hydroxyapatite (PH) and poly(L-lactic acid)/gelatin/hydroxyapatite (PGH) scaffolds respectively. The purpose of this study was to assess and compare bone regeneration potential of electrospun P, PG and electrospun-alternate soaked PH and PGH scaffolds using rat as an animal model by creating two 5 mm circular defects in calvaria. The respective scaffolds were implanted into the defects as one side implantation and both side implantation. Defects left empty served as a negative control for one side implantation and as sham control for both side implantations. The outcomes of the scaffold implantation were determined after 6 and 10 weeks by digital radiography, micro-CT, dual-energy X-ray absorptiometry (DEXA) and histological analysis. PGH scaffold regenerated maximum amount of new bone with high bone mineral density (BMD) into the defects and complete closure occurred in just 6 weeks while other scaffolds failed to close the defects completely. PGH group exhibited highest BMD value after 10 weeks. Histological findings showed abundant osteoblasts and initiation of matrix mineralization in HA containing scaffolds. Masson's trichrome staining showed collagen deposition in all scaffold groups except sham control group. Biochemical and haematological parameters were well with in normal range, indicating no infection due to scaffold implantation. These results prove PGH scaffold as a potential biomaterial for bone regenerative medicine.