Glycoprotein 130 Inhibitor Ameliorates Monocrotaline-Induced Pulmonary Hypertension in Rats

Background: Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction, vascular remodelling, and microthrombotic events. Inflammatory cytokine interleukin (IL-6) may be a key factor in the development of PAH, and glycoprotein 130 (Gp130) is an important signal-transducing subunit of IL-6. The aim of our study was to evaluate the effectiveness of Gp130 inhibitor in reducing inflammation and ameliorating PAH-related vascular remodelling in monocrotaline (MCT)-exposed rats.

Methods: Sprague-Dawley rats (n = 96; weight, 240-250 g) were randomly divided into 3 groups: control, MCT-exposed (MCT), and MCT-exposed plus Gp130 inhibitor (MCT-Gp) administered daily (5 mg/kg) from days 14-28. Eight rats were killed in each group at weeks 1 through 4, with the following measured variables compared across groups on day 28: hemodynamics, right ventricular hypertrophy, morphometric measurements, immunohistochemical results, levels of IL-6, phosphorylated signal transducer and activator of transcription 3, proliferating cell nuclear antigen (PCNA), bone morphogenetic protein receptor-2 (BMPR2), proangiogenic factor, vascular endothelial growth factor (VEGF), proproliferative kinase extracellular signal-regulated kinase (ERK), survivin, Bcl-2, and Bax.

Results: Compared with the MCT group, Gp130 inhibitor, after MCT exposure, improved hemodynamics and significantly reduced the severity of inflammation, as estimated by levels of IL-6 (P < 0.0001), and reversed pulmonary arterial remodelling, as assessed by medial wall thickness (P < 0.0001). Gp130 inhibitor upregulated BMPR2 expression in MCT-exposed lungs (P = 0.040) and decreased the expression of PCNA, VEGF, ERK, and survivin (all P < 0.05).

Conclusions: Gp130 inhibitor upregulated BMPR2 expression in MCT-exposed lungs, restored the BMPR2/IL-6 balance, reduced IL-6-associated inflammation, inhibited pulmonary artery smooth muscle cell proliferation, and ameliorated pulmonary vascular remodelling in MCT-induced PH in rats.