This study is to determine the regulation of nitric oxide synthase 3 (NOS3) by edaravone in mice with hypoxic pulmonary hypertension (HPH). C57BL/6J mice were reared in a hypoxic chamber. HPH mice were treated with edaravone or edaravone + L-NMMA (a NOS inhibitor). Lung tissue was collected for histological assessment, apoptosis analysis, and detection of malondialdehyde, superoxide dismutase, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and NOS3. The levels of serum TNF-α and IL-6 were also measured. Immunohistochemistry was used to visualize the expression of α-smooth muscle actin (SMA) in pulmonary arterioles. Edaravone treatment improved hemodynamics, inhibited right ventricular hypertrophy, increased NOS3 expression, and reduced pathological changes, pulmonary artery wall thickness, apoptotic pulmonary cells, oxidative stress, and the expression of TNF-α, IL-6, and α-SMA in HPH mice. L-NMMA treatment counteracted the lung protective effects of edaravone. In conclusion, edaravone might reduce lung damage in HPH mice by increasing the expression of NOS3.

Keywords: Edaravone, Hypertension, pulmonary, Lung injury, Nitric oxide synthase