P21 Improving Osteoarthritis by Regulating the Pyroptosis of Cartilage Cells

Abstract

Background: The regulation of p21 in the pyroptosis of cartilage cells still needs to be further clarified. We aimed to explore the regulation of p21 on the pyroptosis of cartilage cells and to reveal the improvement of osteoarthritis.
 Methods: Chondrocytes were collected and isolated from patients with osteoarthritis (average age 58.64 ± 4.32) in Xuzhou Third People's Hospital, China in 2019, and healthy volunteers (average age 58.23 ± 3.91) were enrolled as the control group. mRNA expression levels of p21 and pyroptosis-related proteins (NLRP3, ASC, total caspase1 and cleaved-Caspase1) were detected by Western blot and real-time PCR. Cell activity, total number of cells and number of dead cells were calculated with CCK-8, MTT. And the regulation of p21 on the pyroptosis of cartilage cells was verified with overexpression and knockdown of p21 in cartilage cells.
 Results: In cartilage cells of patients with osteoarthritis, the transcription and translation levels of pyrolysis-related genes (NLRP3, cleaved-caspase 1, and ASC) significantly increased (P<0.01). p21 expression was up-regulated and positively correlated with the changing trend of pyrolysis-related proteins (P<0.01). Overexpressing p21 genes in normal cartilage cells significantly increased the expression of pyrolysis-related proteins (P<0.01).
 Conclusion: The pyroptosis of cartilage cells is causally related to the process of osteoarthritis, and can be regulated by transcription factor p21, which is a potential therapeutic target for osteoarthritis.