Srolo Bzhtang reduces inflammation and vascular remodeling via suppression of the MAPK/NF-ΚB signaling pathway in rats with pulmonary arterial hypertension

Ethnopharmacological relevance: Srolo Bzhtang (SBT), which consists of Solms-laubachia eurycarpa , Bergenia pur-purascens , Glycyrrhiza uralensis , and lac secreted by Laccifer lacca Kerr (Lacciferidae Cockerell), is a well-known traditional Tibetan medicinal formula and was documented to cure "lung-heat" syndrome by eliminating "chiba" in the ancient Tibetan medical work Four Medical Tantras (Rgyud bzhi). Clinically, it is a therapy for pulmonary inflammatory disorders, such as pneumonia, chronic bronchitis, and chronic obstructive pulmonary disease. However, whether and how SBT participates in pulmonary arterial hypertension (PAH) is still unclear.Aim of the study: We aimed to determine the role of SBT in attenuating pulmonary arterial pressure and vascular remodeling caused by monocrotaline (MCT) and hypoxia. To elucidate the potential mechanism underlying SBT-mediated PAH, we investigated the changes in inflammatory cytokines and mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-Kappa B) signaling pathway.Materials and methods: MCT-and hypoxia-induced PAH rat models were used. After administering SBT for four weeks, the rats were tested for hemodynamic indicators, hematological changes, pulmonary arterial morpho-logical changes, and the levels of interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha in serum and lung tissues. Protein expression of the MAPK/NF-Kappa B signaling pathway was determined using western blotting. Results: SBT reduced pulmonary arterial pressure, vascular remodeling, and the levels of inflammatory cytokines induced by MCT and hypoxia in rats. Furthermore, SBT significantly suppressed the MAPK/NF-Kappa B signaling pathway.Conclusions: To our knowledge, this is the first study to demonstrate that SBT alleviates MCT-and hypoxia-induced PAH in rats, which is related to its anti-inflammatory actions involving inhibition of the MAPK/NF-Kappa B signaling pathway.