Study on specific proteins involved in articular cartilage regeneration activity induced by decalcified bone transplantation

Abstract

Background: Through a comprehensive analysis of the joint synovial fluid produced in the process of rabbit articular cartilage regeneration, the role and characteristics of knee synovial fluid in the process of decalcified bone transplantation-induced articular cartilage regeneration were explored.

Methods: Twenty New Zealand white rabbits (approximately 2.5 kg in weight) were selected, and bilateral distal femoral bones from two randomly selected rabbits were extracted. After decalcification, the bones were cut into 2 mm × 4 cm long decalcified bone strips. Meanwhile, the other 18 rabbits were randomly divided into three groups: the test group (8 rabbits), the positive control group (6 rabbits), and the blank group (4 rabbits). In the test group, the decalcified bone joint was transplanted into the rabbits at the articular cartilage defect; in the positive control group, the articular cartilage defect of the rabbits were treated and put aside; in the blank group, no rabbits were treated. On the day of transplantation, and on the 4th, 8th, 12th, and 16th weeks after transplantation, the joint synovial fluid of each group was taken for two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) analysis, and related database verification and identification, and compared with the positive control group and the blank group.

Results: Using 2D-PAGE to separate various proteins in the synovial fluid of the rabbit knee joints, it was found that there were differential protein spots in the test group compared with the blank group and the positive control group. After conducting a comparative search and query in the UniProt database, through comprehensive analysis, it was finally found that three proteins with molecular weights of 23,429.4, 57,431.4, and 26,071.1 that may be related to the regeneration of articular cartilage appeared in the test group.

Conclusions: In the process of inducing the regeneration of articular cartilage using decalcified bone transplantation, knee joint synovial fluid produced specific proteins, which may play an important role in the regeneration of articular cartilage. These findings may offer novel ideas in laying a foundation for the in-depth study of articular cartilage regeneration.

Keywords: Decalcified bone; articular cartilage regeneration; mass spectrometry analysis; specific protein; two-dimensional gel electrophoresis.

Figure 1

X-ray of decalcified bone transplantation surgery in rabbits. (A,B,C) X-rays of decalcified bone transplantation at 2, 4, and 8 weeks, respectively; (D,E,F) X-rays of decalcified bone transplantation at 12, 16, and 20 weeks respectively.

Figure 2

Comparison of electrophoresis diagrams of joint fluid in each group.

Figure 3

Mass spectrometry identification data of three proteins. (A) Protein spectrum identification result with a molecular weight of 23,429.4. (B) Protein spectrum identification result with a molecular weight of 57,431.4. (C) Protein spectrum identification result with a molecular weight of 26,071.1.