| External factors: | H2O2 |
| Aging type: | Accelerate |
| Aging characteristic: |
| Category: | Chemical compounds |
| Phenotype: | Osteoarthritis |
| Experiment: | Flow cytometry//SA-β-gal activity assay//Cell morphological analysis |
| Description: | When chondrocytes were incubated with 10 ng/ml IL-1β or 50 μM H2O2 for 24 hours, both treatments markedly increased the percentage of cells in the G0/G1phase and reduced the percentage in the S phase.Both stresses induced the chondrocytes to become large and flat and enhanced SA–β-gal activity in the chondrocytes. |
| Target gene: | CAVEOLIN-1//P38MAPK//CII |
| R-EF-Target gene: | Upregulation//--//Downregulation |
| Official symbol(s): | CAVEOLIN-1//P38MAPK//CII |
| Target gene experiment: | qPCR//Western blot//qRT-PCR//ELISA |
| Target gene description: | Quantitative real-time RT-PCR analysis showed that both IL-1β and H2O2 enhanced caveolin 1 mRNA expression in a time-dependent manner, with the peak level occurring at 3 hours after stimulation(n ＝ 3).By Western blot analysis, we confirmed that both IL-1β and H2O2 also induced prolonged up-regulation of caveolin 1 protein expression. Furthermore, pretreatment with the specific p38 MAPK inhibitor SB202190 blocked the enhancement of SA–β-gal activity induced by IL-1β and H2O2.Quantitative real-time RT-PCR revealed a marked reduction in levels of expression of mRNA for CII and aggrecan in chondrocytes 3 days after stress with IL-1β or H2O2. Decreased production of CII from senescent chondrocytes after administration of either stress factor was also confirmed by ELISA (n = 4). |
| Regulatory pathway: | p53-p21-Rb |
| R-EF-Pathway: | -- |
| Official symbol(s): | TP53-CDKN1A |
| Pathway experiment: | Western blot//qRT-PCR |
| Pathway description: | Quantitative real time RT PCR analysis showed increased expression levels of p53 and p21 mRNA in chondrocytes 3 days after stress with IL 1β and H2O2. Western blot analysis demonstrated that caveolin 1 overexpression and both stresses (IL 1β, H2O2) up regulated p53 and p21 protein levels and down regulated phosphorylated Rb protein levels. |
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