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J Bone Miner Res. 2015 Nov;30(11):2044-57. doi: 10.1002/jbmr.2542. Epub 2015 Jul 24.

Blockage of Src by Specific siRNA as a Novel Therapeutic Strategy to Prevent Destructive Repair in Steroid-Associated Osteonecrosis in Rabbits.

Author information

1
Musculoskeletal Research Laboratory, Department of Orthopaedics & Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, PR China.
2
Translational Medicine R&D Center, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, PR China.
3
Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong SAR, PR China.
4
Department of Orthopaedics, Zhongshan Hospital of Dalian University, Dalian, PR China.
5
Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong SAR, PR China.
6
Department of Orthopaedics, The First Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, Guangzhou, PR China.
7
Bone Research Program, ANZAC (Australian and New Zealand Army Corps.) Research Institute, University of Sydney, Sydney, Australia.

Abstract

Vascular hyperpermeability and highly upregulated bone resorption in the destructive repair progress of steroid-associated osteonecrosis (SAON) are associated with a high expression of VEGF and high Src activity (Src is encoded by the cellular sarcoma [c-src] gene). This study was designed to prove our hypothesis that blocking the VEGF-Src signaling pathway by specific Src siRNA is able to prevent destructive repair in a SAON rabbit model. Destructive repair in SAON was induced in rabbits. At 2, 4, and 6 weeks after SAON induction, VEGF, anti-VEGF, Src siRNA, Src siRNA+VEGF, control siRNA, and saline were introduced via intramedullary injection into proximal femora for each group, respectively. Vascularization and permeability were quantified by dynamic contrast-enhanced (DCE) MRI. At week 6 after SAON induction, proximal femurs were dissected for micro-computed tomography (μCT)-based trabecular architecture with finite element analysis (FEA), μCT-based angiography, and histological analysis. Histological evaluation revealed that VEGF enhanced destructive repair, whereas anti-VEGF prevented destructive repair and Src siRNA and Src siRNA+VEGF prevented destructive repair and enhanced reparative osteogenesis. Findings of angiography and histomorphometry were consistent with those determined by DCE MRI. Src siRNA inhibited VEGF-mediated vascular hyperpermeability but preserved VEGF-induced neovascularization. Bone resorption was enhanced in the VEGF group and inhibited in the anti-VEGF, Src siRNA, Src siRNA+VEGF groups as determined by both 3D μCT and 2D histomorphometry. FEA showed higher estimated failure load in the Src siRNA and Src siRNA+VEGF groups when compared to the vehicle control group. Blockage of VEGF-Src signaling pathway by specific Src siRNA was able to prevent steroid-associated destructive repair while improving reconstructive repair in SAON, which might become a novel therapeutic strategy.

KEYWORDS:

OSTEONECROSIS; REPAIR; SIRNA; SRC

PMID:
25917347
DOI:
10.1002/jbmr.2542
[Indexed for MEDLINE]
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