Then we used qPCR to determine 10 identified essential genes (5 up-regulated genes MAPK1, STAT1, TLR4, TLR2, GART; 4 down-regulated genes RPS6, FBL, RPS3, RPS2) in lung tissues of PAH rats and normal rats. The gene discussed is FBL; the disease is pulmonary arterial hypertension.