Chinese Journal of Tissue Engineering Research ›› 2021, Vol. 25 ›› Issue (34): 5465-5472.doi: 10.12307/2021.240

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Effect of modified citrus pectin on chondrocytes

Zhang Yiyun, Wang Ziqiang, Ren Ying, Du Fuchong, Du Bo, Li Xuemin   

  1. Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Biomedical Materials of Tianjin, Tianjin 300192, China
  • Received:2021-01-08 Revised:2021-01-11 Accepted:2021-01-30 Online:2021-12-08 Published:2021-07-27
  • Contact: Li Xuemin, MD, Associate researcher, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Biomedical Materials of Tianjin, Tianjin 300192, China
  • About author:Zhang Yiyun, Master candidate, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Biomedical Materials of Tianjin, Tianjin 300192, China
  • Supported by:
    General Project of National Natural Science Foundation of China, No. 81972043 (to LXM); the Major Collaborative Innovation Project of Chinese Academy of Medical Sciences Medicine and Health Technology Innovation Project, No. 2017-I2M-1-007 (to LXM)

Abstract: BACKGROUND: Galectin-3 is an important proinflammatory factor during articular cartilage injury and the development of osteoarthritis. Therefore, it could be a potential target for the treatment of osteoarthritis. Modified citrus pectin is a competitive inhibitor of galectin-3. However, the effect of modified citrus pectin on cartilage is not unclear.
OBJECTIVE: To investigate the effect of modified citrus pectin on the metabolic activity and genes expression of in vitro cultured chondrocytes and interleukin-1β induced osteoarthritis chondrocytes. 
METHODS: (1) Chondrocytes from rabbit knee were collected and subjected to the treatment of modified citrus pectin of 0 (normal control), 250, 500 or 750 mg/L respectively for 1, 3, and 5 days. (2) Posttreatment experiment of modified citrus pectin: Chondrocytes of rabbit knee were collected. Chondrocytes were pretreated by interleukin-1β for 24 hours, then posttreated with modified citrus pectin of 0 (control), 250, 500 or 750 mg/L respectively for 1, 3, and 5 days. At the same time, a normal control group was set up. (3) Pretreatment experiment of modified citrus pectin: Chondrocytes of rabbit knee were collected. Chondrocytes were pretreating with modified citrus pectin of 0 (control), 250, 500 or 750 mg/L respectively for 6 hours and following by posttreating by interleukin-1β for 1, 3, and 5 days. At the same time, a normal control group was set up. At the corresponding time point, the mRNA levels of type II collagen, aggrecan, SOX9, type I collagen, matrix metalloproteinase 13 and galectin-3 were determined via RT-qPCR. Furthermore, immunofluorescence staining was conducted to examine the synthesis of type II collagen of chondrocytes.
RESULTS AND CONCLUSION: (1) Compared with normal control group, modified citrus pectin treatment with different mass concentrations significantly enhanced chondrocyte viability, upregulated mRNA of SOX9 and type II collagen, and downregulated mRNA of type I collagen, matrix metalloproteinase 13 and galectin-3. (2) Compared with normal control group, interleukin-1β treatment induced downregulation of expression levels of aggrecan, SOX9, and type II collagen, and upregulation of expression levels of galectin-3 and matrix metalloproteinase 13. (3) Compared with interleukin-1β treated groups, interleukin 1β pretreatment + modified citrus pectin treatment up-regulated the expression levels of type II collagen, aggrecan and SOX9, and decreased the expression levels of galectin-3, matrix metalloproteinase 13 and type I collagen. Modified citrus pectin + interleukin 1β posttreatment up-regulated the expression of type II collagen, aggrecan and SOX9, and decreased the expression of type I collagen, galectin-3 and matrix metalloproteinase 13, but up-regulated type II collagen and aggrecan expression levels failed to reach normal cartilage levels. (4) In summary, under the experimental conditions, modified citrus pectin could enhance the proliferation activity of chondrocytes and maintain their phenotype. At the same time, the intervention of modified citrus pectin can change the gene expression of interleukin 1β-induced chondrocytes, and up-regulate the expression of cartilage cell extracellular matrix synthesis and cartilage formation transcription factor-related genes, and down-regulate the expression levels of catabolism, inflammatory factors and dedifferentiation related genes.

Key words: modified citrus pectin, chondrocytes, osteoarthritis, interleukin-1β, gene expression

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