Animal model of pulmonary hypertension

Male Wistar rats (8 weeks old, body weight 200–350 g) were purchased from the Department of Laboratory Animals of the University of South China. Animals were assigned to two groups (40/group): an MCT-induced pulmonary hypertension group and an age-matched sham-treated control group. The pulmonary hypertension group was induced with a single intraperitoneal (i.p.) injection of MCT (50 mg/kg; 1 mL/100 g body weight). Rats in the control group were injected with an equal volume of phosphate-buffered saline (PBS). MCT was purchased from Sigma-Aldrich (St Louis, MO, USA) and freshly dissolved in 1 M HCl and diluted with PBS (pH 7.0) and 0.1 M NaOH, as previously described.¹⁵ Rats were housed two per cage (one control and one MCT-treated). They were permitted free access to food and water and kept on a 12-hour:12-hour light:dark cycle for 4 weeks after injection. All rats were euthanized by the inhalation of an overdose of CO₂, followed by immediate removal of the heart and kidney, as previously reported.¹⁶ All procedures involving animal experiments were approved by the Department of Laboratory Animals at the University of South China (Protocol number: SYKK (Xiang) 2015-0001).