Xie Xin-Hui, Wang Xin-Luan, He Yi-Xin, Liu Zhong, Sheng Hui, Zhang Ge, Qin Ling
The Chinese University of Hong Kong, Hong Kong, China.
Arthritis Rheum. 2012 May;64(5):1562-71. doi: 10.1002/art.34525.
Cytotherapy is an insufficient method for promoting bone repair in steroid-associated osteonecrosis (SAON), and this has been attributed to impairment of the bioactivity of bone marrow-derived stem cells (BMSCs) after pulsed administration of steroids. Cryopreserved autologous bone marrow-derived mononuclear cells (BMMNCs), which contain BMSCs, might maintain their bioactivity in vitro. This study sought to investigate the effects of cryopreserved BMMNCs, before steroid administration, on the enhancement of bone repair in an established rabbit model of SAON.
For in vitro study, bone marrow was harvested 4 weeks before SAON induction from the iliac crests of rabbits (n = 10) to isolate fresh BMMNCs, and the BMMNCs were then cryopreserved for 8 weeks. Both the fresh and the cryopreserved BMMNCs were evaluated for their bioactivity and osteogenic differentiation capacity. In addition, BMMNCs were isolated 2 weeks after SAON induction and subjected to the same evaluations. For in vivo study, cryopreserved BMMNCs were implanted into the bone tunnel during core decompression of the femur (n = 12 rabbits) after the induction of SAON, and tissue regeneration was evaluated by micro-computed tomography and histologic analyses at 12 weeks postoperation.
In vitro, there were no significant differences in the bioactivity or ability to undergo osteogenic differentiation between fresh BMMNCs and cryopreserved BMMNCs, but after SAON induction, both features were decreased significantly. In vivo, the bone mineral density, ratio of bone volume to total volume of bone, and volume and diameter of neovascularization within the bone tunnel were significantly higher in the BMMNC-treated group compared to the nontreated control group at 12 weeks postoperation.
Cryopreserved BMMNCs maintained their bioactivity and promoted bone regeneration and neovascularization within the bone tunnel after core decompression in this rabbit model of SAON.
细胞疗法在促进类固醇相关骨坏死（SAON）的骨修复方面效果欠佳，这被认为是脉冲式给予类固醇后骨髓源性干细胞（BMSC）生物活性受损所致。含有BMSC的冷冻保存自体骨髓源性单核细胞（BMMNC）在体外可能维持其生物活性。本研究旨在探讨在已建立的兔SAON模型中，在给予类固醇之前冷冻保存的BMMNC对增强骨修复的影响。
体外研究方面，在诱导SAON前4周从兔（n = 10）的髂嵴采集骨髓以分离新鲜BMMNC，然后将BMMNC冷冻保存8周。对新鲜和冷冻保存的BMMNC的生物活性和成骨分化能力进行评估。此外，在诱导SAON后2周分离BMMNC并进行相同评估。体内研究方面，在诱导SAON后，于股骨核心减压时将冷冻保存的BMMNC植入骨隧道（n = 12只兔），术后12周通过微计算机断层扫描和组织学分析评估组织再生情况。
体外，新鲜BMMNC与冷冻保存的BMMNC在生物活性或成骨分化能力方面无显著差异，但在诱导SAON后，这两个特征均显著降低。体内，术后12周时，与未治疗的对照组相比，BMMNC治疗组骨隧道内的骨矿物质密度、骨体积与总体积之比以及新血管化的体积和直径均显著更高。
在该兔SAON模型中，冷冻保存的BMMNC在核心减压后维持了其生物活性，并促进了骨隧道内的骨再生和新血管化。
