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背景:股骨头内硬化带是激素性股骨头坏死疾病发展过程中重要的影像学特征并与预后相关.过氧化物酶体增殖物活化受体γ协同刺激因子1α(peroxisome proliferator-activated receptor gamma coactivator 1α,PGC-1α)被证明具有成骨、促血管形成、抗线粒体凋亡等生物活性,与激素性股骨头坏死的骨修复可能存在紧密关联. 目的:筛选激素性股骨头坏死硬化带区与正常区的差异蛋白,筛选出硬化带的关键蛋白,并验证关键蛋白在激素性股骨头坏死股骨头标本中的差异表达;探索激素性股骨头坏死硬化带修复模式. 方法:取激素性股骨头坏死行人工全髋关节置换术取出的股骨头标本,通过串联质谱标签技术筛选硬化带区与正常区的差异表达基因,并进行GO与KEGG信号通路分析,构建关键靶点的蛋白互作网络、筛选关键基因.观察关键蛋白在激素性股骨头坏死硬化带中的表达,通过Western blotting、免疫组化验证关键蛋白在硬化带中的表达. 结果与结论:①通过串联质谱标签定量蛋白质谱检测发现:相比于正常区骨组织,股骨头硬化带骨组织中具有显著差异表达(Log2FC＞1.20、Log2FC＜0.84和 P＜0.05)的蛋白质有609个,其中发生上调的蛋白质290个,发生下调的蛋白质319个;②通过GO与KEGG通路富集分析,发现在前10位的富集通路中,Wnt信号通路与生命周期调控通路与骨修复关系密切;在生命周期调控通道中,PGC-1α是重要的蛋白之一;③与激素性股骨头坏死标本正常区相比,Western blotting验证了PGC-1α、NRF-1在硬化带中低表达,Cleaved Caspase-3在硬化带中高表达;④光镜下免疫组化结果显示,股骨头组织标本中硬化区及正常区的PGC-1α、NRF1及Cleaved Caspase-3阳性染色分布,可以发现骨小梁、成骨细胞和骨髓均有表达存在;硬化带区Cleaved Caspase-3表达更为明显;⑤结论:激素性股骨头坏死硬化带中存在包含Wnt等成骨相关通路活跃、以PGC-1α低表达为特征的氧化凋亡活跃等生物学行为;PGC-1α在激素性股骨头坏死硬化带中低表达可能与氧化凋亡活跃相关.
BACKGROUND:The sclerotic zone in the femoral head is an important imaging feature in the progression of steroid-induced femoral head necrosis,which is associated with disease prognosis.Peroxisome proliferator-activated receptor γ coactivator 1α(PGC-1α)has been shown to possess biological activities such as osteogenesis,angiogenesis and anti-mitochondrial apoptosis,which may be closely related to bone repair of steroid-induced femoral head necrosis. OBJECTIVE:To screen for the differential proteins in the sclerotic zone of steroid-induced osteonecrosis of the femoral head versus the normal zone,to screen for hub proteins in the sclerotic zone,and to verify the differential expression of hub proteins in the femoral head specimens following steroid-induced femoral head necrosis,and to to explore the repair pattern of the sclerotic zone following steroid-induced femoral head necrosis. METHODS:Femoral head samples were collected from patients with steroid-induced osteonecrosis of the femoral head receiving total hip arthroplasty.The differentially expressed genes in the sclerotic zone and the normal zone were screened by Tandem Mass Tags and analyzed by GO and KEGG signaling pathways to construct a protein-protein interaction network and screen hub genes.In addition,the expression of hub genes in the sclerotic zone was verified by immunohistochemistry and western blot. RESULTS AND CONCLUSION:Quantitative protein profiling by Tandem Mass Tags revealed that 609 proteins were significantly differentially expressed(Log2FC＞1.20,Log2FC＜0.84 and P＜0.05)in the sclerotic zone of the femoral head compared with the normal zone,of which 290 proteins were upregulated and 319 proteins were downregulated.The GO and KEGG pathway enrichment analyses revealed that among the top 10 enriched pathways,Wnt signaling pathway and life-cycle regulatory pathway were closely related to bone repair;in the life-cycle regulatory pathway,PGC-1α was one of the important proteins.In addition,western blot results verified the low expression of PGC-1α and NRF1 in the sclerotic zone and high expression of Cleaved Caspase-3 in the sclerotic zone compared with the normal zone of steroid-induced femoral head necrosis specimens.Light microscopic immunohistochemical results showed the distribution of PGC-1α,NRF1 and Cleaved Caspase-3 positive expression in the sclerotic and normal zones in the femoral head tissue specimens,indicating the presence of their expression in bone trabeculae,osteoblasts and bone marrow.In contrast,the brown area of the sclerotic zone of femoral head necrosis stained darker and showed more obvious expression of Cleaved Caspase-3.To conclude,in the sclerotic zone of steroid-induced femoral head necrosis,biological behaviors including activation of osteogenesis-related pathways such as Wnt and oxidative apoptosis characterized by low expression of PGC-1 are observed.Low expression of PGC-1α in the sclerotic zone of steroid-induced femoral head necrosis may be associated with the activation of oxidative apoptosis.