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Objective To investigate the role of KAT7 in cartilage cell and tissue ageing by establishing an over-replicating-induced primary mouse cartilage cell ageing model and a mouse natural ageing model.Methods Chon-drocytes of the mouse knee joint were obtained by type Ⅱ collagenase digestion and identified by toluidine blue stai-ning and Col Ⅱ staining.The age-related proteins and KAT7 expression levels in cartilage cells from different gener-ations of mice were discovered using Western blot and cellular immunofluorescence techniques,and the aging of the cells was assessed by SA-β-Gal coloring.The pathological alterations were examined in the joints of 22-month-old mice compared to 2-month-old mice using HE staining and safranin O-solid green staining.Additionally,immuno-histochemical analysis was done to observe the expression of KAT7 and p53 in mouse joint tissue.Results Com-pared with the control group,the expression levels of KAT7 protein and p21 and p53 in aged mouse chondrocytes significantly increased.WM-3835,a commonly inhibitor of KAT7 that possess the capacity on halting the protein expression procedure of gene KAT7 as well as p21 in ageing chondrocytes.SA-β-Gal staining showed a significant increase in positive staining of chondrocytes in the eighth generation(P8)compared to the first generation(P1).Compared with the cartilage tissue of young mice,the cartilage tissue of elderly mice presents a near-bone distribu-tion,with a decrease in cartilage surface integrity,a significant increase in the number of hypertrophic chondro-cytes,and more KAT7 and p53 cells that were positive.Conclusion The expression of KAT7 increases in the ageing chondrocytes and the cartilage tissue of ageing mice,reveales the potential significance of KAT7 correlated to cellular aging process in cartilage.
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Objective @# To study the protective effect and mechanism of iPSC⁃MSCs on cartilage matrix in knee oste⁃ oarthritis (KOA) patients in vitro. @*Methods @#Cartilage tissues removed from KOA patients with joint replacement surgery were collected and subjected to tissue and cellular experiments , respectively. Cartilage tissue was cut into small pieces and randomly divided into a control group , an IL⁃1β ( 10 ng/ml) induction group , and iPSC⁃MSCs 96 h and then co⁃cultured with different amounts of iPSC⁃MSCs ( 1 × 104 , 1 × 105 , 1 × 106 ) cells for 72 h. For in tissues , the pathological changes of isolated cartilage tissues were examined by HE staining. The levels of ADAMTS⁃4 , ADAMTS⁃5 , and type II collagen expression were analyzed by immunohistochemistry , while the levels of MMP13 , IL⁃6 , and IL⁃10 in culture supernatants were detected by ELISA kits. The 2 to 5 generations of chondrocytes , which were extracted from cartilage tissue of KOA patients , were stimulated with IL⁃1β ( 10 ng/ml) for 48 h and then co⁃cultured with different concentrations of iPSC⁃MSCs ( 1 × 104 , 1 × 105 , 1 × 106 ) cells for 72 h. Immunofluorescence and Western blot detected the expression of RUNX2 , ADAMTS⁃4 , and ADAMTS⁃5 in chondrocytes. @*Results @#Comparison with the control group , in the IL⁃1β⁃induced group , the levels of RUNX2 , ADAMTS⁃4 , and ADAMTS⁃5 increased , the level of type II collagen decreased , the levels of MMP⁃13 and IL⁃6 in the culture supernatant increased ( P < 0. 05) , and the level of IL⁃10 decreased ( P < 0. 05) ; Compared with the IL⁃1β⁃induced decreased the expression of RUNX2 , ADAMTS⁃4 , and ADAMTS⁃5 , promoted type II collagen expression and elevated IL⁃10 levels. @*Conclusion @#iPSC⁃MSCs inhibited ADAMTS⁃4 and ADAMTS⁃5 expression in vitro , reduced cartilage extracellular matrix degradation , and played a role in articular cartilage protection.