PTGS2 and systemic sclerosis: the expression levels of NOX4, PTGS2, and LYN showed an upward trend (Figure 6A) in hypoxia-treated fibroblasts and SSc, and the expression level of aldehyde dehydrogenase 1A1 (ALDH1A1), epidermal growth factor (EGF), DNA nucleotidylexotransferase (DNTT), transketolase (TKT), ACAA2, and ALDH3A1showed a downward trend in hypoxia-treated fibroblasts and SSc (Figures 6B).