Purpose: We investigated the role of human platelet gel (PG) embedded within gelatin (Gel) scaffold on healing of critical-sized radial bone defects in rats. Methods: Twenty-five Sprague-Dawley rats were randomly divided into five equal groups. In each animal, critical-sized 5-mm bone defects were created in the radial bones of both forelimbs (n = 10/group). The defects were then either left untreated or filled with autograft, Gel, PG or Gel-PG. Before euthanasia, the healing defects were evaluated radiologically and clinically. The animals were euthanized after eight weeks and their radial bones evaluated by radiography, computed tomography (CT) scan, histology, biomechanical testing and ultrastructural evaluations. Results: PG implantation significantly increased cellular differentiation, osteoblastic proliferation and consequently new bone formation so that those defects treated with PG showed superior structural and biomechanical properties to the Gel and PG-Gel-treated defects. The PG-treated defects had radiological, morphological and mechanical properties closely comparable with those of the autograft group. In contrast, in the PG-Gel group, Gel significantly reduced the beneficial effects of PG on bone healing. Conclusions: Human PG had beneficial effects on bone regeneration, while combination of PG and Gel had no remarkable beneficial effect. Therefore, PG when used alone can be regarded as a promising osteoinductive and osteoconductive option in bone tissue engineering applications.

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