Molecular analysis of Leukemia Inhibitory Factor, LIF, signal transduction specific to the bone

为了阐明颅面骨的特征，我们在有胎牛血清、无血清和细胞因子（碱性成纤维细胞生长因子，bFGF）的培养基条件下，检测了临床经验丰富的先天性半面肥厚患者来源的培养成骨细胞样细胞的增殖活性。细胞增殖与胎牛血清浓度及无血清培养基中bFGF呈剂量依赖性。bFGF中和抗体显著降低细胞增殖和DNA合成，提示外源性细胞因子治疗可调节先天性面肌肥厚患者源性成骨细胞。这引发了局部细胞因子对颅面骨调节的概念。通过对双皮质固定与单皮质固定对下颌矢状面劈开截骨术后下牙槽神经紊乱的比较研究，我们发现两种固定方式对下牙槽神经紊乱的影响无显著性差异，但单皮质固定对下牙槽神经紊乱的影响明显少于双皮质固定。这可能是由于原位骨重塑加速和增强骨愈合而不需要刚性固定的原因。局部因子如细胞因子和生长因子可能参与局部骨的形成。通过对Le Fort I型唇腭裂患者截骨术后复发的分析，我们发现上颌运动方向、数量、手术方式和类型对术后复发和偏离有显著影响，平均时间为2年半。这是与骨重塑和随后的稳定性有关的局部因素的另一个证据。在这些临床验证的基础上，我们设计了大鼠颅骨缺损模型，并对局部细胞因子基因治疗进行了测试。白血病抑制因子（Leukemia Inhibitory Factor， LIF）是一种众所周知的骨增强因子，其信号转导机制也得到了充分的研究。因此，我们试图阐明局部LIF基因在表达载体中是否会促进颅骨骨缺损的骨形成。术后三周，LIF增加DEXA法显示的骨密度。在组织学上，与对照组相比，fif基因处理的组织中有更多的骨细胞。免疫组织化学和原位杂交显示，在LIF处理的组织中，LIF信息明显增加。这些数据表明，局部LIF是通过信号转导和表达来促进骨形成的。建议今后进一步研究与LIF表达相关的转录因子和转录调节因子。少

In order to elucidate the craniofacial bone characteristics, clinically experienced congenital hemifacial hypertrophic patient-derived cultured osteoblast-like cells were tested the cell proliferation activity under media condition with fetal calf serum, serum free, and cytokine (basic fibroblast growth factor, bFGF). Cell proliferation was dose-dependent on the fetal calf serum concentration, and bFGF in serum free media. The neutralizing antibody to bFGF significantly decreased the cell proliferation and DNA synthesis, suggesting that congenital hemifacial hypertrophic patient-derived osteoblast is regulated by exogenous cytokine treatment. This provoked the concept of the regulation of the craniofacial bone by the local cytokines. In comparative study of inferior alveolar nerve disturbance after mandibular sagittal split osteotomy by means of bicortical versus monocortical fixation, we found that there are no significant difference on bone fixation in both methods, however, the nerv … More e disturbance was significantly less frequent in monocortical fixation. This may explain there is no need of rigid fixation because the bone remodeling in situ accelerate and enhance the bone healing. Local factors such as cytokines and growth factors may be involved in the local bone formation. In the analysis of relapse after Le Fort I osteotomy in patients with cleft lip and palate, we elucidated the direction of the maxillary movement, amount, operative procedure and type of the cleft significantly affect the post-operative relapse and deviation during averaged two and half years period. This is another evidence of the local factors affiliating the bone remodeling and subsequent stability. Based on these clinical verifications, we designed the rat cranial bone defect model and tested the local cytokine gene therapy. Leukemia Inhibitory Factor, LIF, is not only well-known bone enhancing factor but its signal transduction is fully investigated. Therefore, we sought to clarify the local LIF gene in a expression vector would enhance the bone formation in cranial bone defect. LIF increased the bone mineral density shown by DEXA methods by three weeks post-operatively. In histology, there are more osteocytes in LIF-gene treated tissues than the control vehicle. LIF messages indicated by Immunohistochemistry and in situ hybridyzation were markedly increased in LIF-treated tissues. These data suggest local LIF is signally transduced and expressed to enhance the bone formation. Further study related to transcriptional factors and transcription-regulating factors associated with LIF expression are suggested in the future. Less