Figure 3: Effect of transcutaneous CO2 application on oxygenation in a mouse model of human MFH. Mice were treated with CO2 or control air three days after MFH cell implantation. Tumors were isolated from mice at 0, 6 and 24 h after CO2 gas treatment. (A) Protein expression of HIF-1a decreased time-dependently by 24 h post-transcutaneous CO2 treatment. (B) Consistent with HIF-1a expression, mRNA expression of VEGF in tumors showed a time-dependent decrease at 24 h post-CO2 treatment. The expression after 24 h of treatment was significantly decreased compared with before treatment (*p < 0.05).