SOD1 and colitis: The upregulation was even greater in mice with DSS-induced colitis that underwent the HBO2 treatment (DSS + HBO2 group; Figure 4(b)). SOD1 mRNA expression was significantly reduced in the colon of the DSS + HBO2 group compared to CTRL (P = 0.008) and CTRL + HBO2 (P = 0.007) groups.