Hypoxia-inducible factor prolyl hydroxylase inhibitor prevents steroid-associated osteonecrosis of the femoral head in rabbits by promoting angiogenesis and inhibiting apoptosis.

Lihong Fan,Jia Li,Xiaoqian Dang,Zefeng Yu,Kunzheng Wang,Bart O Williams

doi:10.1371/journal.pone.0107774

Abstract

The purpose of this study was to investigate the preventive effect of ethyl 3,4-dihydroxybenzoate(EDHB) on steroid-associated femoral head osteonecrosis(ONFH) in a rabbit model. New Zealand white rabbits were randomly divided into two groups (prevention group and model group), each containing 24 rabbits. Osteonecrosis was induced by lipopolysaccharide(LPS) combined with methylprednisolone(MPS). The prevention group received an intraperitoneal injection of EDHB at 50 mg/kg body weight every other day starting three days before establishing rabbit models of osteonecrosis, for a total of nine doses. Osteonecrosis was verified by haematoxylin-eosin (HE) staining. The expression of HIF-1α and VEGF was analyzed by immunohistochemistry. Angiogenesis, apoptosis and microstructural parameters were also analyzed. The rabbit models of osteonecrosis were successfully established and observed by HE staining. Histopathological observations indicated that EDHB reduced the rate of empty lacunae and the incidence of osteonecrosis. Immunohistochemical staining for HIF-1α and VEGF suggested that EDHB therapy inhibited degradation of HIF-1α and promoted expression of VEGF. Ink artery infusion angiography and microvessel density analysis revealed that there were more microvessels in the prevention group than in the model group. The TUNEL apoptosis assay suggested that EDHB intervention could reduce the number of apoptotic cells in avascular osteonecrosis of the femoral head. Micro-CT scanning indicated that the treatment group had better microstructural parameters than the model group. EDHB prevents steroid-associated osteonecrosis of the femoral head in rabbits by promoting angiogenesis and inhibiting apoptosis of bone cells and hematopoietic tissue.

Highlights

Steroid-associated osteonecrosis of the femoral head(ONFH), which is characterized by trabecular bone necrosis and bone marrow necrosis, is an aseptic and ischemic disease caused by long-term glucocorticoid use or heavy use over a short period of time
EDHB reduced the rate of empty lacunae, the average bone marrow fat cell size and the incidence of osteonecrosis
During the establishment of steroid-associated femoral head osteonecrosis model, four rabbits in the model group died of infection and were excluded from the evaluation

Summary

Introduction

Steroid-associated osteonecrosis of the femoral head(ONFH), which is characterized by trabecular bone necrosis and bone marrow necrosis, is an aseptic and ischemic disease caused by long-term glucocorticoid use or heavy use over a short period of time. The pathogenesis of steroid-associated ONFH is not clearly understood. Steroid-associated ONFH is a common disease which is both progressive and refractory. It accounts for the majority of the ONFH [2] and brings great suffering to families and society. If not treated properly and promptly, 80% of the femoral heads will collapse once the osteonecrosis process begins [3]. It is highly desirable to develop promising methods to prevent steroid-associated ONFH, slow down the collapse of the articular surface and avoid or delay the need for hip arthroplasty

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Conclusion