The Effect And Mechanism Of Sodium Tanshinone ⅡA Sulfonate On Hypoxic Pulmonary Hypertension

Aims:To investigate the effect and mechanism of sodium tanshinone IIA sulfonate(STS)on hypoxic pulmonary hypertensionMethods:Healthy male Sprague-Dawley rats were housed in a hypoxic chamber with an oxygen concentration of(10±1)%for 8 hours a day for 21 days to establish a hypoxic pulmonary hypertension model.Rats were divided to five groups:Normoxia,Hypoxia,Hypoxia+STS Low-dose,Hypoxia+STS High-dose,and Hypoxia+LY294002(an inhibitor of PI3K/Akt/mTOR signaling pathway).Pulmonary arterial pressure was measured by a cardiac function analysis system,lung tissue was sampled to calculate the ratio of lung in wet weight to dry weight,and pathological changes of each group was observed by hematoxylin eosin staining.Western blot analysis was applied to examine the protein expressions in apoptosis,PI3K/AKT/mTOR and autophagy signaling pathways in lung tissue.The inflammatory factors of IL-6,IL-8,TNF-a in lung tissue were tested by ELISA.Results:1 The pressure of pulmonary arterialThe results showed that under anesthesia condition pulmonary artery pressure in the Hypoxia group was significantly higher than that in the Normoxia group(P<0.05).It was markedly decreased in Hypoxia+STS low-dose group and Hypoxia+STS high-dose group compared with Hypoxia group(P<0.05),indicating that STS can relieve pulmonary hypertension.2 The index of Right heart ventricular hypertrophyThe index of right heart ventricular hypertrophy of rats was significantly higher in Hypoxia group than that of Normoxia rats(P<0.05).It was markedly suppressed in Hypoxia+STS Low-dose group and Hypoxia+STS High-dose group compared with Hypoxia group(P<0.05).3 The ratio of lung in wet weight to dry weightThe ratio of lung in wet weight to dry weight showed that hypoxia significantly increases the ratio by comparing the Hypoxia group with Normoxia group(P<0.05).STS treatments both in low and high dose groups and LY294002 treatment reduce the ratio compared with Hypoxia group(P<0.05).4 Hematoxylin Eosin stainingHistopathological analysis showed that the percentage of medial artery wall thickness to artery outer diameter,the percentage of medial artery wall area to medial artery area in the Hypoxia group were significantly higher than those of in the Normoxia group(P<0.05).It was markedly suppressed in Hypoxia+STS Low-dose group and Hypoxia+STS High-dose group compared with Hypoxia group(P<0.05).5 Apoptosis-related proteinsExpressions of apoptosis-related proteins showed that under hypoxia condition the anti-apoptotic protein Bcl-2 in the lung tissues was significantly increased compared with Normoxia group(P<0.05).High-dose STS and LY29400 treatments significantly suppressed the Bcl-2 expression compared with that in Hypoxia group(P<0.05).At the same time,the expression of proapoptotic protein Bax in the lung tissue of Hypoxia group was lower than that in Normoxia group(P<0.05).Treatment with STS and LY294002 increase the expression of Bax compared with Hypoxia group(P<0.05).The ratio of Bcl-2/Bax was significantly lower in Hypoxia group compared with Normoxia group(P<0.05),High dose of STS treatment increased the ratio of Bcl-2/Bax(P<0.05).6 The protein expressions of PI3K/Akt/mTOR and autophagy signaling pathwayThe expressions of PI3K/Akt/mTOR signal-related proteins(PI3K,Phosphor Akt,mTOR,70S6,S6K1)were increased in Hypoxia group compared with Normoxia group(P<0.05),It was markedly suppressed in Hypoxia+STS high-dose group and Hypoxia+LY294002 group compared with Hypoxia group(P<0.05).The expression of autophagy-related proteins was negatively correlated with the PI3K/Akt/mTOR signaling pathway,expressions of Beclin-1 and LC3 were reduced and expression of p62 was increased in Hypoxia group compared with Normoxia group(P<0.05).High dose of STS and LY294002 treatments reversed hypoxic-induced changes of Beclin-1,LC3 and p62(P<0.05).7 Inflammatory factors about IL-6,IL-8,TNF-aThe levels of inflammatory factors show that contents of IL-6,IL-8,TNF-a in lung tissue of the Hypoxia group were significantly higher than those in the Normoxia group(P<0.05).After treatment with STS,contents of those inflammatory factors in lung tissue were significantly lower than those in Hypoxia group(P<0.05).Conclusions:1.Sodium tanshinone IIA sulfonate can alleviate hypoxic pulmonary hypertension.2.The possible mechanism of the protective effect of sodium tanshinone IIA sulfonate is by promoting apoptosis,inhibiting PI3K/AKT/mTOR,up-regulating autophagy signal pathways,also by inhibiting inflammatory response,suppressing intimal hyperplasia via inhibition of proliferation and migration of vascular smooth muscle.