Experimental observation of the sequence of tibial plateau chondrocyte and matrix degeneration in spontaneous osteoarthritis in Guinea pigs

Xiao-Jian Wang,Yan Xue,Rong-Shan Li,Lei Wei

doi:10.1186/s12891-021-04281-x

Abstract

BackgroundTo observe the sequence of chondrocyte degeneration and matrix degradation in the superficial surface cartilage of the tibial plateau in guinea pigs with spontaneous knee osteoarthritis (OA).MethodsSixty guinea pigs were euthanized at the ages of 8 months (n = 20),10 months (n = 20) and 12 months (n = 20) respectively. The degree of degeneration of the tibial plateau cartilage was evaluated by Osteoarthritis Research Society International (OARSI) score. The levels of Aggrecan,CollagenX,MMP-13 and Caspase-3 in the chondrocytes were detected by immunohistochemistry (IHC). The serum concentration of CTX-II was measured and compared. Western blot analysis was used to detect the levels of Aggrecan,CollagenX,MMP-13 and Caspase-3 in the cartilage tissue.ResultsThe OARSI scores both in 8-month-old group and 10-month-old group were lower than that in the 12-month-old group. The levels of Aggrecan in articular chondrocyte were higher both in 8-month-old group and 10-month-old group than that in 12-month-old group. The level of Collagen X increased with the age of guinea pigs. And the levels of MMP-13 and caspase-3 both in 10-month-old group and 12-month-old group were higher than those in 8-month-old group. The concentration of CTX-II in serum increased significantly in 12 months old group.ConclusionThe superficial chondrocytes of the tibial plateau first appeared to be hypertrophic and then apoptotic, and the matrix was further degraded when spontaneous knee osteoarthritis occurred in guinea pigs. Changes in the physiological state of chondrocytes are the initiating factors in the pathogenesis of knee OA.

Highlights

To observe the sequence of chondrocyte degeneration and matrix degradation in the superficial surface cartilage of the tibial plateau in guinea pigs with spontaneous knee osteoarthritis (OA)
The results showed that the safranin O staining patterns of the tibial plateau superficial surface cartilage tissue both in the 8-month-old group 10month-old group were intact, the surface of the superficial surface cartilage was smooth and exhibited no damage or obvious longitudinal cracks, and some superficial surface chondrocytes showed hypertrophic changes in 10-monthold group
In order to observe the biological properties of the superficial chondrocytes, IHC was used to detect the expression levels of Aggrecan protein, CollagenXprotein and MMP-13 protein, the markers of physiological state of chondrocytes, and Caspase-3 protein,a marker of apoptotic chondrocytes,in superficial chondrocytes

Summary

Introduction

To observe the sequence of chondrocyte degeneration and matrix degradation in the superficial surface cartilage of the tibial plateau in guinea pigs with spontaneous knee osteoarthritis (OA). The most obvious and typical pathological changes in knee OA are pathological changes to articular cartilage tissues: chondrocytes become hypertrophic and apoptotic, their number is reduced, cartilage matrix is degraded, and knee OA occurs. The data show that articular cartilage tissues are composed of chondrocytes and extracellular matrix secreted by chondrocytes. It is currently believed that when OA occurs, the superficial zone of cartilage tissue is the first to be affected, and the cartilage matrix and chondrocytes undergo corresponding changes [7,8,9]. When OA-initiating factors appear on superficial cartilage tissue, whether the cartilage matrix or chondrocytes degenerated firstly remain unclear [2, 10, 11]

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