OBJECTIVE To investigate the effect and underlying mechanism of hydroxytyrosol(HT)on mouse chondrocyte injury induced by oxidative stress.METHODS Mouse chondrocytes were incubated with varying concentrations of HT 0-400 μmol L-1 for 24 h,and the viability of the mouse chondrocytes was assessed using CCK-8 kit.An oxidative stress model of chondrocytes was estab-lished by the addition of H2O2 200 μmol L-1.The experimental groups included the cell control group,H2O2 group,and H2O2+HT 10,50 and 250 μmol·L-1 groups.After 24 h,the mRNA expression levels of interleukin-6(IL-6),cyclooxygenase-2(COX-2),prostaglandin E2(PGE2),inducible nitric oxide synthase(iNOS),matrix metalloproteinase-3(MMP-3),MMP-13,a disintegrin and metalloproteinase with throm-bospondin motifs-4(ADAMTS-4),ADAMTS-5,SRY-box transcription factor-9(SOX-9)and aggrecan(ACAN)in mouse chondrocytes were detected by real-time quantitative PCR,the intracellular reactive oxygen species(ROS)level in chondrocytes was measured with 2,7-dichlorodihydrofluorescein diace-tate(DCFH-DA)staining,while the mitochondrial membrane potential was evaluated using JC-1 staining.After 48 h,the protein expression levels of iNOS,COX-2,MMP-13,and type Ⅱ collagen(Col-2)in mouse chondrocytes were detected using Western blotting.RESULTS HT at concentrations≤350 μmol·L-1 had no significant effect on the survival of mouse chondrocytes.Compared with the cell control group,after 24 h,the mRNA expression levels of IL-6,COX-2,PGE2,iNOS,MMP-3,MMP-13,ADAMTS-4 and ADAMTS-5 in the chondrocytes of mice in the H2O2 group were increased,while the mRNA expression levels of SOX-9 and ACAN were decreased.Additionally,there was an elevation in the ROS level and a significant loss of mitochondrial membrane potential in the chondrocytes of mice.Compared with the H2O2 group,after treatment with HT 10,50 and 250 μmol·L-1,there were significant decreases in mRNA expression levels of IL-6,COX-2,PGE2,iNOS,MM P-3,MMP-13,ADAMTS-4 and ADAMTS-5,the mRNA expressions of SOX-9 and ACAN were increased,the ROS level was lowered.After treatment with HT 50 and 250 μmol L-1,the loss of mitochondrial membrane potential was ameliorated.Compared to the cell control group,the protein expressions of iNOS,COX-2 and MMP-13 were upregulated in the H2O2 group,while the protein expression of Col-2 was downregulated after 48 h.Compared to the H2O2 group,treatment with HT at concentrations of 10,50 and 250 μmol·L-1 resulted in decreased protein expressions of iNOS,COX-2 and MMP-13 in mouse chondrocytes,but the protein expression of Col-2 increased following treatment with HT 50 and 250 μmol L-1.CONCLUSION HT can ameliorate H2O2-induced chondrocyte injury by reducing intracellular ROS levels and alleviating the loss of mitochondrial membrane potential,suppressing the release of inflammatory cytokines,inhibiting catabolic processes,and promoting anabolic activities.

OBJECTIVE To investigate the effect and underlying mechanism of hydroxytyrosol(HT)on mouse chondrocyte injury induced by oxidative stress.METHODS Mouse chondrocytes were incubated with varying concentrations of HT 0-400 μmol L-1 for 24 h,and the viability of the mouse chondrocytes was assessed using CCK-8 kit.An oxidative stress model of chondrocytes was estab-lished by the addition of H2O2 200 μmol L-1.The experimental groups included the cell control group,H2O2 group,and H2O2+HT 10,50 and 250 μmol·L-1 groups.After 24 h,the mRNA expression levels of interleukin-6(IL-6),cyclooxygenase-2(COX-2),prostaglandin E2(PGE2),inducible nitric oxide synthase(iNOS),matrix metalloproteinase-3(MMP-3),MMP-13,a disintegrin and metalloproteinase with throm-bospondin motifs-4(ADAMTS-4),ADAMTS-5,SRY-box transcription factor-9(SOX-9)and aggrecan(ACAN)in mouse chondrocytes were detected by real-time quantitative PCR,the intracellular reactive oxygen species(ROS)level in chondrocytes was measured with 2,7-dichlorodihydrofluorescein diace-tate(DCFH-DA)staining,while the mitochondrial membrane potential was evaluated using JC-1 staining.After 48 h,the protein expression levels of iNOS,COX-2,MMP-13,and type Ⅱ collagen(Col-2)in mouse chondrocytes were detected using Western blotting.RESULTS HT at concentrations≤350 μmol·L-1 had no significant effect on the survival of mouse chondrocytes.Compared with the cell control group,after 24 h,the mRNA expression levels of IL-6,COX-2,PGE2,iNOS,MMP-3,MMP-13,ADAMTS-4 and ADAMTS-5 in the chondrocytes of mice in the H2O2 group were increased,while the mRNA expression levels of SOX-9 and ACAN were decreased.Additionally,there was an elevation in the ROS level and a significant loss of mitochondrial membrane potential in the chondrocytes of mice.Compared with the H2O2 group,after treatment with HT 10,50 and 250 μmol·L-1,there were significant decreases in mRNA expression levels of IL-6,COX-2,PGE2,iNOS,MM P-3,MMP-13,ADAMTS-4 and ADAMTS-5,the mRNA expressions of SOX-9 and ACAN were increased,the ROS level was lowered.After treatment with HT 50 and 250 μmol L-1,the loss of mitochondrial membrane potential was ameliorated.Compared to the cell control group,the protein expressions of iNOS,COX-2 and MMP-13 were upregulated in the H2O2 group,while the protein expression of Col-2 was downregulated after 48 h.Compared to the H2O2 group,treatment with HT at concentrations of 10,50 and 250 μmol·L-1 resulted in decreased protein expressions of iNOS,COX-2 and MMP-13 in mouse chondrocytes,but the protein expression of Col-2 increased following treatment with HT 50 and 250 μmol L-1.CONCLUSION HT can ameliorate H2O2-induced chondrocyte injury by reducing intracellular ROS levels and alleviating the loss of mitochondrial membrane potential,suppressing the release of inflammatory cytokines,inhibiting catabolic processes,and promoting anabolic activities.

Objective To investigate the mechanism underlying gasdermin E(GSDME)-mediated pyroptosis in radiation-induced intestinal injury and to find out whether gasdermin(GSDM)family members regulate pyroptosis through similar signaling pathways.Methods Human normal colon epithelial cells(NCM460)and human colon cancer cells(HT-29)were exposed to radiation of different doses and durations before pyroptosis indicators were evaluated by observing pyroptotic bubbles,cell survival,and the cleavage of pyroptosis execution proteins.HT-29 cells overexpressing GSDME were subjected to radiation,followed by enrichment analysis of pyroptosis-related differentially expressed genes using RNA-seq.Results Radiation induced substantial pyroptosis in NCM460 cells.Overexpression of GSDME in HT-29 cells resulted in substantial radiation-induced pyroptosis.The pyroptosis state of human intestinal cells was simulated in the HT-29 model cell line.Overexpressions of GSDME-N and GSDMD-N resulted in the expression of more than 50％ of the differentially expressed genes in the pyroptosis state.Sequencing analysis showed that the genes in the pyroptosis state were mainly overrepresented in immune response,inflammatory response,and Rapl signaling pathway.Conclusion GSDME activation can mediate radiation-induced pyroptosis by producing GSDME-N fragments.GSDM family members participate in pyroptosis in a similar mode of regulation.Furthermore,radiation-induced activation of GSDME/D may regulate pyroptosis through immune response,inflammatory response,and Rap1 signaling pathway.