Our study found 6 upregulated mitochondrial genes (Psmd2, Psmc4, Psmc3, Psmc5, Psmd13, and Psmc2) and 3 downregulated mitochondrial genes (Lipe, Cat, and Prkce) which are significantly differentially expressed in the lung tissue of PAH rats. The gene discussed is PSMC5; the disease is pulmonary arterial hypertension.