Histological and immunohistochemical investigation of mesenchymal stem cells, biphasic calcium phosphate ceramics and the platelet rich plasma's effects of bone regeneration on rat calvarial critical size defects

According to the new technological developments, many new treatment methods and biomaterials are used to restore the bone defects. In oral and maxillofacial region; due to malformation, infection, trauma or resection; structural and functional reconstruction problems of bone defects are not satisfactorily dissolved and this can be faced as the most difficult problem in contemporary reconstructive surgery. In some cases, it is inevitable to use bone grafts and biomaterials in order to heal extensive bone defects.In this study, our aim is to investigate the effects of biomaterials (such as biphasic calciumphosphate, platelet rich plasma and mesenchymal stem cell) used in oral and maxillofacial surgery on osteogenesis and to compare these materials in terms of osteonectin / osteopontin enzyme expression and effects on osteocyte density.In our study the effectiveness of the mesenchimal stem cells, platelet rich plasma and biphasic calcium phosphate which has avoked a curiosity recently, was investigated in critical size cranial defects of rats.This study was planned on ninety wistar female rats. Ten rats were used to obtain platelet rich plasma. The remainders were separated into five groups. A full thickness circular bone defect (7 mm in critical size) was created in the frontal bone of each rat. Group I (n=6) was operative control group. In Group II (n=21) biphasic calcium phosphate, in Group III (n=21) biphasic calcium phosphate and platelet rich plasma combination, in Group IV (n=21) biphasic calcium phosphate and mesenchimal stem cell combination, in Group V (n=21) biphasic calcium phosphate , platelet rich plasma and mesenchimal stem cell combination were applied into the defects. At the end of the 2th, 8th and 12th week, all of the rats were sacrificed. In histologic and immunohistochemical evaluation amoung groups, osteoblastic activity and osteogenesis patterns are considered. Additionally osteopontin and osteonectin enzyme expression level and osteocyt density are evaluated statistically and compared.At the conclusion of the study, osteoblastic activity and osteogenesis are ideally occured in the 12th week. Therefore preparate were painted positively with osteonectin and osteopontin. Graft+Platelet rich plasma+Mesenchymal stem cell group was the most effective in inducing new bone formation (osteogenesis). This group is followed by Graft+ Platelet rich plasma and only Graft used group. Also regular bone formation and osteoinduction were detected, even in a critical size defect, in the Graft+ Platelet rich plasma+Mesenchymal stem cell group.Higher level of osteogenesis (two times greater than other groups) is a significant finding that avokes the thought of an ideal reconstruction material for critical size defect is Graft+ Platelet rich plasma+Mesenchymal stem cell combination.Statistically the significant result of group comparison was obtained from Graft+ Platelet rich plasma+Mesenchymal stem cell, 2nd only Graft group (p=0,005), Graft+Mesenchymal stem cell and only graft group (p=0,028), Graft+ Platelet rich plasma and Graft+ Platelet rich plasma+Mesenchymal stem cell groups (p=0,031).Key Words: Mesenchymal stem cell, platelet rich plasma, biphasic calcium phosphate, osteogenesis, critical size bone defect