Degradation of subchondral bone collagen in the weight-bearing area of femoral head is associated with osteoarthritis and osteonecrosis

Zongyi Wu,Zijian Shen,Sheji Weng,Jingdong Zhang,Lei Yang,Deyi Yan,Zhongjie Xie,Jiahao Tang,Bingli Bai,Liang Chen,Bingzhang Wang

doi:10.1186/s13018-020-02065-y

Abstract

BackgroundThe aim of the study was to evaluate the change of subchondral bone collagen and trabecular bone in the weight-bearing area of femoral head from patients with osteoarthritis (OA) or osteonecrosis of femoral head (ONFH), and discuss the effect of collagen degradation on OA and ONFH.MethodsFemoral heads from patients with femoral neck fracture (FNF) were collected as control group. All collected samples were divided into OA group (N = 10), ONFH group (N = 10), and FNF group (N = 10). Differences of subchondral bone collagen were compared through scanning electron microscope (SEM) observation, immunohistochemistry staining, and Masson’s trichrome staining. Alteration of subchondral bone was displayed through hematoxylin and eosin (H&E) staining and gross morphology.ResultsSEM results showed that collagen fibers in OA and ONFH group appeared to be thinner, rougher, sparser, and more wizened. Immunohistochemistry and Masson’s trichrome staining results demonstrated that the content of collagen fibers in the OA and ONFH group was obviously less than the FNF group. H&E staining results showed that trabecular bone in OA and ONFH group appeared to be thinner and ruptured. Gross morphology results showed that the degeneration and destruction of cartilage and subchondral bone in OA and ONFH group were severer than FNF group. The characteristics mentioned above in ONFH group were more apparent than OA group.ConclusionsThis study revealed that degradation of collagen fibers from subchondral bone in the weight-bearing area of femoral head was associated with OA and ONFH, which may help to find new therapeutic strategies of the diseases.

Highlights

The aim of the study was to evaluate the change of subchondral bone collagen and trabecular bone in the weight-bearing area of femoral head from patients with osteoarthritis (OA) or osteonecrosis of femoral head (ONFH), and discuss the effect of collagen degradation on OA and Osteonecrosis of femoral head (ONFH)
Chipman SD et al revealed in an animal experiment that mice with the type I collagen mutation oim present with fewer and thinner trabeculae in the femoral head compared with their wild-type counterparts [2]
Several studies have demonstrated that the changes of subchondral bone may be an important etiological element in the development of OA [8,9,10], and animal experiments found that morphological changes in the subchondral bone prior to articular cartilage manifestations [11,12,13]

Summary

Introduction

The aim of the study was to evaluate the change of subchondral bone collagen and trabecular bone in the weight-bearing area of femoral head from patients with osteoarthritis (OA) or osteonecrosis of femoral head (ONFH), and discuss the effect of collagen degradation on OA and ONFH. The impairment of subchondral bone collagen is one of the key reasons that account for the occurrence and development of OA and ONFH. Both ONFH and OA are accompanied by subchondral bone damage, the mechanism of injury is different. In ONFH, degeneration and necrosis of subchondral bone are associated with decreased vascular supply, while in OA, subchondral bone damage may be affected by degeneration of articular cartilage and its own microfractures [19]. There may be differences in the alteration of collagen fibers in subchondral bone tissue between ONFH and OA. The study was designed to investigate the differences of subchondral bone collagen and trabecular bone among patients with OA, ONFH, or femoral neck fracture (FNF) through scanning electron microscope (SEM) observation, immunohistochemistry staining, Masson’s trichrome staining, hematoxylin and eosin (H&E) staining, and gross morphology observation

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