PM2.5 Exposure Aggravates Left Heart Failure Induced Pulmonary Hypertension

Particulate matter 2.5 (PM2.5) exposure is high risk to cardiovascular diseases. We investigated the influence of PM2.5 exposure on pulmonary arterial hypertension (PAH) murine model induced by left ventricular (LV) failure. Thirty 10 weeks old C57BL/6 mice were randomised to four groups: sham group, sham + PM2.5 group, TAC group, and TAC + PM2.5 group. Eight weeks post TAC surgery, right ventricular (RV) and lung remodelling (Sirius Red staining and WGA Staining), heart and lung function (EF and RVSBP), and fibrotic genes (TGF-ti mRNA expression and collagen III protein level in lung tissue were measured. Exposure to PM2.5 augments TAC induced PAH as evidenced by decreased EF value and increased RVSBP, RV cardiomyocytes size, RV and lung fibrosis, and upregulated expression of collagen III and TGF-a in comparison to TAC group in lung tissues. Even the LV EF value was deceased from 79.3 ± 3.4% to 63.4 ± 2.1% when sham group exposed to PM2.5, PM2.5 exposure had no effect on RVSBP, RV cardiomyocytes' size, RV weight/tibia length, RV and lung fibrosis, and expression of collagen III and TGF-a in sham surgery mice. Exposure to PM2.5 aggravates deterioration of LV failure induced PAH.