Repair of calvarial defects in rabbits with platelet-rich plasma as the scaffold for carrying bone marrow stromal cells.

OBJECTIVE: Platelet-rich plasma (PRP) is becoming a new application in tissue engineering and a developing area for clinicians and researchers because it is a natural source of growth factors, many of which can accelerate and promote bone regeneration. However, few studies have reported the potentiality of using PRP as a scaffold in bone tissue engineering. The present study investigated the feasibility of using PRP as a scaffold to carry bone marrow stromal cells (BMSCs) to repair calvarial defects in a rabbit model. STUDY DESIGN: The primary cultured BMSCs were divided into 2 groups. One group was induced with dexamethasone and the other was not induced. Full-thickness bone defects of 5-mm diameter (4 defects per calvarium) were created on the calvaria of 10 New Zealand white rabbits. PRP or whole blood was used, respectively to incorporate the induced or uninduced BMSCs. Then, the composites were activated and applied to repair the defects. The samples were harvested 8 weeks later and bone regeneration was assessed grossly and analyzed by radiographic or histologic examination. RESULTS: Eight weeks after the implantation of the materials, substantial bone regeneration was observed at the calvarial defect restored with PRP incorporating the induced BMSCs. Less new bone formation was observed at the defect implanted with PRP incorporating the uninduced BMSCs. In contrast, no bone regeneration was detected at the defects implanted with the whole blood incorporating BMSCs, whether the BMSCs were induced or not. CONCLUSIONS: PRP can be used as a scaffold to carry in vitro expanded BMSCs to repair a rabbit's calvarial defect, but its inductive ability to BMSCs was limited.

Diaqua-bis(2,2'-biimidazole)zinc(II) 4,4'-di-carboxybiphenyl-3,3'-di-carboxyl-ate.

In the title compound, [Zn(C(6)H(6)N(4))(2)(H(2)O)(2)](C(16)H(8)O(8)), the Zn(II) atom, located on an inversion centre, is coordinated by two aqua and two bidentate biimidizole ligands, resulting in a slightly distorted octa-hedral ZnO(2)N(4) geometry. The four N atoms from the two biimidizole ligands lie in the equatorial plane and the two aqua O atoms lie in the axial sites. The biphenyl-tetra-carboxyl-ate anion also lies on an inversion centre. The Zn(II) complex cation and the anion are held together by N-H⋯O hydrogen bonds, forming a zigzag chain along [21]. The chains are further connected by water mol-ecules via O-H⋯O hydrogen bonds.