The Effects Of Sodium Tanshinone ⅡA Sulphonate On Seawater-induced Acute Lung Injury In Rats And Its Mechanism

Danshen has been clinically used alone or in combination with other herbal ingredients in China to manage cardiovascular diseases, cancer and other diseases. It is an herbal drug derived from the dried root or rhizome of Salvia miltiorrhiza Bunge. Tashinone IIA （TIIA） is one of the main active components of Danshen. Recent reports showed that TIIA ameliorated lung injury caused by Lipopolysaccharide （LPS）. However, the effects of TIIA on seawater drowning-induced acute lung injury are not fully understood.1 ObjectiveIn this study, we investigated the role of apoptosis in seawater drowning-induced ALI, and explored whether TIIA preserves lung integrity and attenuate the acute lung injury induced by seawater by inhibiting lungtissue cell apoptosis through the activation of the Akt and ERK survival pathways.2 MethodsThe rats were randomly divided into three groups after acclimatization. Naive Group: no seawater and TIIA was given, and the other treatment conditions were the same as the SW Group. SW Group: The rats were anaesthetized with 20% urethane （1.0 g·kg） intraperitoneally. Then, a 1ml syringe was inserted into trachea and 4 ml/kg body weight of seawater was injected with a steady speed in 4 min into both lungs. TIIA/ SW Group: 50mg/kg TIIA was instilled intraperitoneally 10 min after seawater intratracheal instillation.3 ResultsThe results demonstrated that TIIA treatment significantly improved seawater exposure-induced lung histopathological changes, alleviated the decrease in PaO₂, SO₂ and pH and the increase in PaCO₂, and reduced cell infiltration in BALF, lung oedema and vascular leakage. As revealed by terminal deoxynucleotidyl transferase-mediated nick end labelling （TUNEL） assay, seawater intratracheal instillation induced the apoptosis of lung tissue cells. Besides, seawater intratracheal instillation also changed apoptosis-related factors, caspase-3 and Bcl-2, and the activation of Akt and ERK1?2 decreased immediately after seawater exposure. Furthermore, the treatment of TIIA decreased apoptosis, reversed changes in Bcl-2 and caspase-3, and reversed seawater exposure induced reduction in the activation of Akt and ERK1?2. 4 ConclusionTaken together, the data firstly demonstrate that seawater intratracheal instillation induced cell apoptosis in lung tissues, and apoptosis might play an important role in seawater drowning-induced lung injury. Furthermore, TIIA could significantly attenuate the severity of lung tissue cell apoptosis and ALI in seawater-challenged rats, which is possibly partly by modulation of the activation of Akt and ERK1/2 pathways. The Aquaporins （AQPs） are a family of transmembrane water channels and are expressed on plasma membranes of many cell types, facilitate water transport across cell membranes. AQPs play a major role in transcellular and transepithelial water movement. AQP1 and AQP5 are two particularly important proteins in the lung that increase water permeability in response to osmotic gradients. The precise role that AQP1 and AQP5 play in acute lung injury （ALI） or lung inflammation is still controversial. It is still unknown what role of AQP1 and AQP5 plays in seawater exposure-induced ALI and whether pharmacologic modulation of AQP1 and AQP5 could alleviate the severity of ALI caused by seawater intratracheal instillation.1 ObjectiveIn the present study, the aim is to investigate the changes of AQP1 and AQP5 in seawater exposure-induced ALI and explore the effect of TIIA on lung injury and the expression of AQP1 and AQP5 in seawater-challenged rats.2 MethodsAnimal experimentThe rats were randomly divided into three groups after acclimatization. Naive Group: no seawater and TIIA was given, and the other treatment conditions were the same as the SW Group. SW Group: The rats were anaesthetized with 20% urethane （1.0 g?kg） intraperitoneally. Then, a 1ml syringe was inserted into trachea and 4 ml/kg body weight of seawater was injected with a steady speed in 4 min into both lungs. TIIA/ SW Group: 50mg/kg TIIA was instilled intraperitoneally 10 min after seawater intratracheal instillation.Cell experimentA549 cells, a human lung epithelial cell line, cultured routinely were divided into three teams: negative control group, 25% seawater group, 25ug/ml TIIA treatment group. After incubated in the presence or absence of 25ug/ml TIIA, 25% seawater were added to A549 cells, then the cells of three groups were all stimulated for the 4 h. At the end of the experiment, the cells were collected. The expressions of AQP1 and AQP5 in A549 cells exposured by seawater were detected by Western blotting and Immunohistochemistry.3 ResultsIn this study, the results of Western blotting, Immunohistochemistry and RT-PCR showed that intratracheal installation of seawater up-regulated the protein levels and mRNA of AQP1 and AQP5 in lung tissues of rats. Besides, treatment of tanshinone IIA ameliorated lung histopathologic changes and blood-gas indices, alleviated vascular leakage and lung edema. Treatment of TIIA also significantly reduced the elevation of AQP1 and AQP5 expression induced by seawater exposure both in rats and A549 cells.4 ConclusionThese data demonstrated that AQP1 and AQP5 were up-regulated after seawater aspiration, which might play an important role in the development of lung edema and lung injury. TIIA could markedly improve seawater exposure-induced ALI, which was may be through the inhibition of AQP1 and AQP5 over-expression in lungs of seawater-challenged rats.