Chinese Journal of Tissue Engineering Research ›› 2018, Vol. 22 ›› Issue (16): 2526-2531.doi: 10.3969/j.issn.2095-4344.0761

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Roles of cytochrome C and Caspase-9 in steroid-induced avascular necrosis of the femoral head

Gong Yu-lin1, Wang Yu-xin2, Zhao Zhen-qun3, Li Hong-bin1   

  1. 1Department of Rheumatology and Immunology, the Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010059, Inner Mongolia Autonomous Region, China; 2Department of Bone Oncology, 3Department of Pediatric Orthopedics, the Second Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010030, Inner Mongolia Autonomous Region, China
  • Received:2018-03-09 Online:2018-06-08 Published:2018-06-08
  • Contact: Zhao Zhen-qun, Master, Associate chief physician, Department of Pediatric Orthopedics, the Second Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010030, Inner Mongolia Autonomous Region, China Corresponding author: Li Hong-bin, M.D., Chief physician, Department of Rheumatology and Immunology, the Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010059, Inner Mongolia Autonomous Region, China
  • About author:Gong Yu-lin, Master, Attending physician, Department of Rheumatology and Immunology, the Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010059, Inner Mongolia Autonomous Region, China Wang Yu-xin, Master, Physician, Department of Bone Oncology, the Second Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010030, Inner Mongolia Autonomous Region, China Gong Yu-lin and Wang Yu-xin contributed equally to this work.
  • Supported by:

    the National Natural Science Foundation of China, No. 81760391; the Natural Science Foundation of Inner Mongolia Autonomous Region, No. 2015MS08121

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Abstract:

BACKGROUND: Steroid-induced avascular necrosis of the femoral head (SANFH) may be associated with apoptosis of osteocytes, but its regulatory mechanism remains unclear. Cytochrome C and Caspase-9 are key factors in the mitochondrial apoptosis signaling pathway, and their roles in SANFH still need further investigation.
OBJECTIVE: To investigate the roles of cytochrome C and Caspase-9 in the SANFH.
METHODS: Twenty New Zealand white rabbits were randomly divided into experimental and control groups (n=10 per group). Rabbits in the experimental group were injected with 7.5 mg/kg methylprednisolone, twice weekly, and those controls were subjected to the injection of same amount of normal saline. The treatment period was 8 weeks in both group.The rabbits were then sacrificed by air embolism to remove the bilateral femoral head specimens for histological and transmission electron microscope observations. The apoptotic cells were detected by TUNEL method and the expression levels of cytochrome C and Caspase 9 were detected by immunohistochemistry.
RESULTS AND CONCLUSION: Eight weeks after intervention, compared with the control group, the experiment group had loose femoral head, thinned trabecular bone, increased adipocytes in the medullary cavity, and increased percentage of empty lacunae (P < 0.05); the apoptotic bodies were formed, and the apoptosis rate was increased (Р < 0.05); and the positive expression rates of cytochrome C and Caspase-9 were significantly increased (P < 0.01). Correlation analysis results showed that the apoptosis rate was positively correlated with the empty lacunae rate and the positive expression rates of cytochrome C and Caspase-9 (P < 0.01). These findings indicate that the abnormal release of cytochrome C and high expression of Caspase-9 are related to the apoptosis of osteocytes in SANFH.

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words: Hormones, Femur Head Necrosis, Apoptosis

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