The Influence Of Mitochondrial ATP-sensitive Potassium Ion Channels On The Proliferation And Secretion Of Human Airway Smooth Muscle Cells In Asthma

Objective:Bronchial asthma is a serious disease threat to human health. It is characterized by chronic airway inflammation, airway remodeling and airway hyperresponsiveness (AHR), in which chronic airway inflammation is considered to be the nature of asthma. It was considered that airway smooth muscle cells in the pathological process are only as a passive target cells, there are corresponding response of contraction and spasm by the stimulation of inflammatory mediators. However, studies have shown that ASMCs have not only systolic function, but also can change from the contractile type into synthetic phenotype of proliferation with the stimulation of the external environmental factors, synthesizing and secreting various inflammatory factors and cytokines recently, The specific mechanism is very complicated. Our previous study found that asthma can induce the MitoKATP channel of ASMCs opening and promote ASMCs proliferation and phenotype, which involved in airway remodeling. But the research about the MitoKATP channel of human bronchial airway smooth muscle cells(HASMCs) is still rarely reported. In this study, Building on previous studies of MitoKATP channel, we intend to explore the role of MitoKATP channel on HASMC proliferation and secretion in asthma, searching for the new way of asthma prevention and treatment.Methods:Normal HASMCs were isolated and cultured from the lung tissue of patients undergoing lobectomy. Asthma HASMCs were induced by the way of normal HASMCs sensitizing passively to serum of asthmatics. Normal and asthmatic HASMCs were divided into six groups: normal control group; normal + diazoxide (mitochondrial ATP-sensitive potassium channel selective activator) group; normal +5-hydroxydecanoate(5-HD) (mitochondrial ATP-sensitive potassium channel selective antagonist) group; asthma control group; asthma + diazoxide group; asthma +5-hydroxydecanoate group. Mitochondrial membrane potential (△ψm) were detected using rhodamine (R-123) staining; laser scanning confocal microscope image; intracellular reactive oxygen species (ROS) were quantified applying 2, 7 - dichloro dihydro fluorescein diacetate (DCFH-DA) fluorescence; mRNA expression of transforming growth factorβ₁ (TGF-β₁) was detected with RT-PCR.Results:â‘ Compared with the control group, the fluorescence of R-123 became more intensive; the depolarization of the△ψm occured; ROS generation and cell proliferation were increased, the expression of TGF-β₁ was also increased in the normal+Diazoxide group (P <0.05). However, the difference between the normal+5-HD group and the normal control group was not significant.;②△ψm in asthma group depolarized; the fluorescence of R-123intensity, the generation of ROS and the expression of TGF-β₁ increased in asthma group in comparision to the normal control group while they were decreased in asthma +5- HD group compared with the asthma control group (P <0.05). conclusion :Asthma can cause the opening of the mitochondrial membrane ATP-sensitive potassium ion channel in HASMCs, the increase of the production of ROS, and the depolarization of△ψm. Asthma may promote HASMC's proliferation and transformation to the synthetic phenotype, TGF-β₁ ,also increase, may involve the airway remodeling and the development of asthma.