The expression of FTO, ALKBH5, METTL3 and YTHDF1 were determined by quantifying overlap between the red and green signals, which revealed a faint fluorescence intensity for FTO and strong fluorescence intensity for YTHDF1 in small pulmonary arteries of MCT-PAH rats lung tissue, while no significant differences for ALKBH5 and METTL3 were found in the pulmonary vessels (Figures 5, 6). This evidence concerns the gene YTHDF1 and pulmonary arterial hypertension.