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

Comparative bone regeneration study of hardystonite and hydroxyapatite as filler in critical-sized defect of rat calvaria

There is a very significant and well-known clinical need for the development of new osteoinductive materials and the establishment of alternative therapies for the treatment of bone tissue loss or failure resulting from injury or disease as the transplantation of tissues in patients with these injury or disease is severely limited by donor scarcity and is highly associated to the risk of immune rejection and disease transfer. Herein, we studied in vivo bone response by quantifying efficacy and safety of three scaffold variations: (1) nanofibrous polycaprolactone (PCL), (2) PCL-hydroxyapatite (HA), and (3) PCL-hardystonite (HS) against SHAM as the control. Diffraction pattern from TEM showed that native HA and HS were polycrystalline and they leached higher ppm of calcium, phosphorus and zinc as compared to PCL-HA and PCL-HS in which HA, HS were incorporated in PCL nanofibers. The study was performed on 8 mm critical-sized rat calvarial defects analyzed at two timepoints, 6 and 12 weeks. The bone regenerated by PCL-HS promoted higher growth than that by SHAM and PCL alone at 12 weeks with comparable bone mineral density in all groups at both time points. PCL-HS showed potential for bone growth similar to that for PCL-HA. Histology data showed dense bone interface being formed at the site in both the PCL-HS and PCL-HA groups. Therefore, HS was found to have comparable functionality with commercial HA. No significant differences were noted in any of the blood parameters but there were differences in serum biochemistry parameters of triglyceride and creatine levels among groups, which are indirectly related to bone forming potential and directly to safety of kidney function, while the other parameters were unchanged and within the normal range. Thus, we conclude that the HS material can be a suitable substitute for bone tissue engineering