osteoprotegerin and Fractures--Ununited

This study aims to evaluate the effects of local adipose stem cell injection on non-union and diabetic non-union of rat femurs.. Forty-eight female Wistar albino rats (weighing mean 200 g and aged 8 weeks) were used in this study. The rats were divided into six groups. Group 1 was chosen as a reference for receptor activator of nuclear factor-kappa (κ) B (RANK), receptor activator of nuclear factor-κ B ligand (RANKL) and osteoprotegerin (OPG) genes and no femur osteotomy was performed in this group. Group 2 underwent femur osteotomy, the osteotomy was fixed with a 1.5 mm K-wire as retrograde from the knee joint, and no gap was left in the osteotomy line. In order to induce non-union, femurs underwent osteotomy fixed with K-wires in groups 3, 4, 5 and 6. In addition, the osteotomy line was measured as 1.8 mm gap with electronic calipers and the gap was fixed with U staple. Before osteotomy, streptozocin was injected intraperitoneally at a dose of 60 mg/kg in 0.1 mol/L citrate buffer solution (Ph 4.4) in groups 4 and 6, in order to induce diabetes mellitus. Left femur anteroposterior and lateral X-rays were taken 10 weeks after the operation and the union in group 2 and non-union in groups 3, 4, 5, and 6 were confirmed. To see if injection of adipose stem cells into the non-union site increases bone union, 2 mL 0.9% sodium chloride (NaCl) in groups 3 and 4 and 2×106 adipose stem cell in groups 5 and 6 were locally injected into the non-union area with fluoroscopy. Femur X-rays were taken eight weeks after the injection and all rats were sacrificed. Femurs of rats were removed for histopathological and gene expression evaluation.. There were significant differences between the groups injected 0.9% NaCI and adipose stem cells in terms of bone healing according to radiological and histopathological evaluations (p<0.05). No statistically significant difference was observed between the groups in terms of gene expression levels.. According to the results of our study, local adipose stem cell injection has positive radiological and histopathological effects in diabetic and non-diabetic femoral non-unions, independently of RANK, RANKL, or OPG gene expression pathways.

Topics: Adipocytes; Animals; Female; Femur; Fracture Healing; Fractures, Ununited; Osteoprotegerin; Osteotomy; RANK Ligand; Rats; Rats, Wistar; Receptor Activator of Nuclear Factor-kappa B; Stem Cell Transplantation

Delayed bone healing, especially in long bones poses one of the biggest problems in orthopeadic and reconstructive surgery and causes tremendous costs every year. There is a need for exploring the causes in order to find an adequate therapy. Earlier investigations of human scaphoid non-union revealed an elevated osteoclast activity, accompanied by upregulated levels of TGF-beta and RANKL. Interestingly, scaphoid non-union seemed to be well vascularized.. In the current study, we used a murine femur-defect model to study atrophic non unions over a time-course of 10 weeks. Different time points were chosen, to gather insights into the dynamic processes of non-union establishment.. Histological analyses as well as western blots and qRT-PCR indicated enhanced osteoclast activity throughout the observation period, paralleled by elevated levels of TGF-beta, TNF-alpha, MMP9, MMP13 and RANKL, especially during the early phases of non-union establishment. Interestingly, elevated levels of these mediators decreased markedly over a period of 10 weeks, as inflammatory reaction during non-union establishment seemed to wear out. To our surprise, osteoblastogenesis seemed to be unaffected during early stages of non-union establishment.. Taken together, we gained first insights into the establishment process of atrophic non unions, in which inflammatory processes accompanied by highly elevated osteoclast activity seem to play a leading role.

Topics: Animals; Atrophy; Cell Proliferation; Cytokines; Disease Models, Animal; Female; Fractures, Ununited; Inflammation; Inflammation Mediators; Male; Mice, Inbred C57BL; Osteoblasts; Osteoclasts; Osteoprotegerin; RANK Ligand