| Objective:To observe the protective effect of 18?-Glycyrrhetinic Acid on pulmonary arterial hypertension and to explore its mechanism.Methods:A rat model of pulmonary arterial hypertension was established by subcutaneous injection of monocrotaline 60 mg/kg in a single neck of Sprague-Dawle rats and a model of pulmonary artery smooth muscle cell proliferation was established by stimulation with 20 ng/ml PDGF-BB.Rat hemodynamic parameters?mPAP,RVSP?were detected by right heart catheterization.Right ventricular hypertrophy?RVHI?was measured by organ weighing method.H.E staining was used to observe the morphological changes of rat pulmonary vessels.Observation of collagen fiber proliferation in rat lung tissue by Masson staining.The smooth muscle actin??-SMA?was detected by immunohistochemical staining.The expression of RhoA,ROCK1and ROCK2 protein in rat lung tissue was detected by Western blot.The effect of18?-Glycyrrhetinic Acid on the proliferation of HPASMCs was investigated by cell proliferation assay.Flow cytometry was used to detect the effect of18?-Glycyrrhetinic Acid on the cell cycle of HPASMCs.The expression of RhoA,ROCK1,ROCK2,t-MYPT1,p-MYPT1,p27kip1,Bax and Bcl-2 in HPASMCs were detected by Western blot.The effects of 18?-Glycyrrhetinic Acid on the expression of RhoA,ROCK1 and ROCK2 mRNA in HPASMCs were detected by RT-qRCR assay.Results:Compared with the control group,the hemodynamic parameters and RVHI of the model group were significantly increased.The levels of m PAP,RVSP and RVHI in the 18?-Glycyrrhetinic Acid?50,100 mg/kg?dose group were significantly lower than those in the model group;The results of H.E staining showed that compared with the control group,the pulmonary arterial wall of the model group was significantly thickened and the lumen area of the vessel was narrow.The 18?-Glycyrrhetic Acid?50,100 mg/kg?dose improved the remodeling of the small arterioles in the rat lung;The Masson staining results of the tissue sections showed that the collagen fibers in the lung tissue of the MCT group were significantly proliferated,and the muscle fibers were not arranged continuously.18?-Glycyrrhetinic Acid?50,100 mg/kg?significantly ameliorated the collagen fibrosis rats with PAH.The muscle fibers are arranged in a row and tend to be neat;The immunohistochemical staining showed that the expression level of?-SMA in the lung tissue of the model group was significantly evaluated.Treatment with 18?-Glycyrrhetinic Acid?100 mg/kg?reduced the expression level of?-SMA in rat lung tissue;Western blot analysis showed that18?-Glycyrrhetinic Acid?100 mg/kg?could significantly down-regulate RhoA,ROCK1 and ROCK2 in lung tissue of rats with pulmonary hypertension;Cell proliferation assay showed that 18?-Glycyrrhetinic Acid?80,160?M?inhibited the proliferation of HPASMCs;Flow cytometry results showed that 18?-Glycyrrhetinic Acid?80,160?M?blocked the cell cycle of HPASMCs;Western blot analysis showed that 18?-Glycyrrhetinic Acid?160?M?could significantly down-regulate the ratio of RhoA,ROCK1,ROCK2,Bcl-2 and over-high p-MYPT1/t-MYPT1 in HPASMCs and can significantly improve the protein expression of p27kip1,Bax;RT-qRCR results showed that 18?-Glycyrrhetinic Acid?160?M?significantly inhibited RhoA,ROCK1,and ROCK2 mRNA expression in HPASMCs.Conclusion1.The 18?-Glycyrrhetinic Acid has protective effect on MCT-induced pulmonary arterial hypertension in rats.2.The 18?-Glycyrrhetinic Acid inhibits the proliferation of PDGF-BB induced HPASMCs.3.The 18?-Glycyrrhetinic Acid improves the development of pulmonary arterial hypertension through the RhoA/ROCK signaling pathway. |
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