Expression of adiponectin in the subchondral bone of lumbar facet joints with different degrees of degeneration

Qi Lai,Leitao Huang,Jianghao Zhu,Yuan Liu,Min Dai,Hanxiong Cheng,Runsheng Guo,Xionglong Yu,Xuqiang Liu,Qiang Wang,Bin Zhang

doi:10.1186/s12891-017-1786-8

Abstract

BackgroundOsteoarthritis research has been most commonly performed in the setting of the articular cartilage of the knee. To the best of our knowledge, no studies have evaluated the role of adiponectin in osteoarthritis of the lumbar facet joint (FJOA). Therefore, in this study, we explored whether adiponectin was expressed in the lumbar facet joints and evaluated the role of adiponectin in FJOA.MethodsWe enrolled patients who underwent lumbar computed tomography (CT) and magnetic resonance imaging (MRI) at the Orthopedic Department of the First Affiliated Hospital of Nanchang from May 2015 to June 2016. Lumbar facet joints were obtained from 135 patients at the time of lumbar fusion surgery and divided into three groups according to the Weishaupt grade. Cytokine levels in the subchondral bones were evaluated by enzyme-linked immunosorbent assays (ELISAs), and adiponectin levels were determined by immunohistochemistry, western blotting, and quantitative polymerase chain reaction (qPCR).ResultsBy ELISA, adiponectin levels were examined in the subchondral bone for lumbar facet joint, and adiponectin was found to be negatively correlated with BMI in 52 patients (p < 0.001, r = −0.861). By immunohistochemistry analysis, adiponectin was found to be expressed in the subchondral bone of the lumbar facet, whereas the cartilage area was negative for adiponectin expression. Immunostaining intensity and area was related to the degeneration of the lumbar facet joint, and, in our research, considerably decreased staining intensity and area were observed in more severely degenerated lumbar facet joints. Furthermore, the expression of adiponectin was also reduced in degenerated lumbar facet joints, and the level of decline corresponded to degeneration detected by western blotting and qPCR analysis (n = 27, p < 0.0001).ConclusionsAdiponectin expression was observed in the subchondral bone of the lumbar facet joint and decreased as the degree of degeneration increased. Thus, the results of this study provide new insights into the relationship between adiponectin and osteoarthritis.

Highlights

Osteoarthritis research has been most commonly performed in the setting of the articular cartilage of the knee
Lumbar facet joints were divided into three groups according to computed tomography (CT) and magnetic resonance imaging (MRI) results based on Weishaupt grading because of subjective interference in grades 1 and 2 [23]
Expression of IL-1β, Tumour necrosis factor (TNF)-α, leptin, and adiponectin in lumbar facet joints First, we evaluated the expression of several cytokines in lumbar facet joint specimens using Enzyme-linked immunosorbent assay (ELISA)

Summary

Introduction

Osteoarthritis research has been most commonly performed in the setting of the articular cartilage of the knee. To the best of our knowledge, no studies have evaluated the role of adiponectin in osteoarthritis of the lumbar facet joint (FJOA). Lumbar facet joint osteoarthritis (FJOA) is present in approximately 40% of patients with low back pain [1,2,3]. Some studies have shown that knee OA may be a disease of the entire joint, including articular cartilage, subchondral bone, meniscus, ligament, and neuromuscular groups [11, 12]. The subchondral bone plays a major role in knee joint degeneration. Few studies have evaluated lumbar facet OA or the subchondral bone by basic research, with scholars instead focusing more on clinical research areas [13, 14]

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