Intermittent hypoxia (IH) is a direct consequence of obstructive sleep apnea syndrome (OSAS), which results in left ventricular dysfunction , remodeling and myocardial cell injury .Understanding the mechanisms of OSAS is important for us to prevent and treat the cardiovascular complications in the clinical practices .We summarize the effects of IH on left ventricular function , and analyze the mechanisms at the cellular and molecular levels , including oxidative stress, ion exchangers and inflammation .In addition, the effects of endothelin-1 and hypercapnia on IH-induced cardiac injury are discussed .

ObjectiveTo investigate the intervention effect of Buzhong Yiqitang （BZYQT） on pulmonary inflammation in mice induced by chronic intermittent hypoxia （CIH） and preliminarily elucidate its mechanism. MethodForty healthy male C57BL/6 mice aged 6-8 weeks were randomly divided into the following groups： normoxia group， model group （exposed to CIH）， and low-， medium-， and high-dose BZYQT groups. The normoxia group was exposed to a normoxic environment， while the model group and the low-， medium-， and high-dose BZYQT groups were exposed to intermittent hypoxia. In the BZYQT groups， the BZYQT （8.1， 16.2， 32.4 g·kg^-1·d^-1） was administered orally 30 min before placing the mice in the hypoxic chamber， while the model group and the normoxia group received an equivalent volume of normal saline. After five weeks of modeling， pulmonary function of the mice was measured using an EMKA animal lung function analyzer， and lung tissue samples were collected after the pulmonary function tests. Hematoxylin-eosin （HE） staining was performed to observe the histopathological changes in the lung tissue of each group. Enzyme-linked immunosorbent assay （ELISA） was used to measure the levels of interleukin-6 （IL-6）， interleukin-8 （IL-8）， tumor necrosis factor-α （TNF-α） in the serum， as well as angiotensin Ⅱ （Ang Ⅱ） and angiotensin-（1-7） ［Ang（1-7）］ in lung tissue. Western blot and immunohistochemistry were used to detect the protein expression of IL-6， IL-8， TNF-α， angiotensin-converting enzyme 2 （ACE2）， and mitochondrial assembly receptor （Mas）. ResultCompared with the normoxia group， the model group showed significant abnormalities in lung function （P<0.05， P<0.01）， lung tissue changes， such as thickening of alveolar walls and inflammatory cell infiltration， increased levels of IL-6， IL-8， TNF-α in the serum and Ang Ⅱ in lung tissue （P<0.01）， decreased level of Ang（1-7） （P<0.01）， increased protein expression of IL-6， IL-8， and TNF-α， and decreased protein expression of ACE2 and Mas （P<0.05， P<0.01）. Compared with the model group， the BZYQT groups showed improvement in lung function （P<0.05， P<0.01）， and HE staining of lung tissue showed approximately normal alveolar wall thickness and reduced inflammatory cell infiltration. Immunohistochemistry and Western blot analysis showed a significant decrease in the expression of inflammatory-related proteins （P<0.05， P<0.01）， and a significant increase in ACE2 and Mas protein expression （P<0.05， P<0.01）. ConclusionBZYQT can improve lung injury in mice exposed to CIH by regulating the ACE2-Ang（1-7）-Mas axis to inhibit inflammatory responses.

Respiratory diseases are common， frequently-occurring clinical diseases. As the prevalence rate is increasing year by year， they have become a problem that seriously affects public health. The diseases are mainly located in the lung by traditional Chinese medicine （TCM） syndrome differentiation. Lung governs Qi and controls breathing and is also an organ for the storage of phlegm. Clinically， phlegm and Qi are often used for the treatment. Banxia Houputang （BHT）， originated from Synopsis of the Golden Chamber （《金匮要略》）， was used to treat plum-stone Ai （globus hystericus） at first. It is composed of Rhizoma Pinelliae， Cortex Magnoliae Offcinalis， Poria， Rhizoma Zingiberis Recens， and Folium Perillae， and treats diseases with the core pathogensis of mutual obstruction of phlegm and Qi. BHT has the effects of moving Qi， dissipating mass， descending adverse Qi， and resolving phlegm， which basically correspond to the pathological characteristics of the lungs. Clinical studies have confirmed that modified BHT can be used either alone or in combination with western medicine to treat chronic pharyngitis， asthma， chronic obstructive pulmonary disease， pneumonia， obstructive sleep apnea， upper airway cough syndrome and other respiratory diseases， with significant effects. It effectively improves the symptoms and signs of the diseases and reduces the recurrence rate. Basic research has shown that BHT plays anti-inflammatory， anti-oxidative stress， anti-apoptotic， autophagy-regulating， and iron overload-regulating roles by regulating the targets in multiple pathways. This paper， by combing the relevant literature in recent years， conducted a systematic review on BHT from the three aspects of syndrome analysis， clinical treatment research and mechanism research， with a view to providing theoretical basis and reference for the mechanism research of BHT in treating respiratory diseases and for expanding its clinical application.