Abstract: BACKGROUND: Establishing a chondrocyte model of osteoarthritis is of great significance for further explaining the pathological process of osteoarthritis and evaluating and screening the therapeutic drugs of osteoarthritis.
OBJECTIVE: To evaluate the effect of interleukin-1β to induce osteoarthritis models in rat chondrocyte models, thereby providing a reference for further exploration of drug treatment of osteoarthritis.
METHODS: Chondrocytes were isolated from the hip cartilage of 3-week-old Sprague-Dawley rats by mechanical shearing and enzymatic digestion, and then identified. Chondrocytes were randomly divided into three groups: control group, 5 ng/mL interleukin-1β-induced group, 10 ng/mL interleukin-1β-induced group, with induction times of 24 and 48 hours. Chondrocyte proliferation activity was detected by MTT. Real-Time PCR was used to detect the expression of type II collagen, Aggrecan, sex-determining region Y-box protein 9 (Sox9), matrix metalloproteinase 13, and a disintegrin and metaloproteinase with thrombospondin-like motifs-5 (Adamts5) mRNA. Western blot was used to detect the expression of type II collagen, Sox9, matrix metalloproteinase 13 and Adamts5.
RESULTS AND CONCLUSION: Primary rat chondrocytes were successfully isolated and cultured. Induction of chondrocytes by interleukin-1β at 10 ng/mL for 24 hours could significantly reduce cell proliferation and viability (P < 0.05), while the 5 ng/mL interleukin-1β-induced group required 48 hours of induction to cause a significant decrease in cell proliferation and viability. Real-Time PCR results showed that compared with the control group, 5 or 10 ng/mL interleukin-1β induction for 24 and 48 hours significantly reduced the expression levels of type II collagen, Aggrecan, Sox9 mRNAs (P < 0.05) and increased the expression levels of matrix metalloproteinase 13 and Adamts5 mRNAs (P < 0.05). Compared with the 10 ng/mL interleukin-1β-induced group, 5 ng/mL interleukin-1β induction significantly increased the mRNA expression of matrix metalloproteinase 13 and Adamts5 in chondrocytes after 48 hours of induction (P < 0.05). Western blot results showed that compared with the control group, 10 ng/mL interleukin-1β induction for 24 hours and 5 ng/mL interleukin-1β induction for 48 hours significantly decreased the protein expression of type II collagen and Sox9 in chondrocytes (P < 0.05), and significantly increased the protein expression of matrix metalloproteinase 13 and Adamts5 (P < 0.05 ). To conclude, compared with 5 ng/mL interleukin-1β, 10 ng/mL interleukin-1β may have more obvious effects on chondrocytes for 24 hours, while 5 and 10 ng/mL interleukin-1β have similar effects after 48 hours of intervention.

Key words: osteoarthritis, chondrocyte, Interleukin-1β, rat, cell viability