scholarly journals A Flow Cytometry-based Assay for Measuring Mitochondrial Membrane Potential in Cardiac Myocytes After Hypoxia/Reoxygenation

10.3791/57725 ◽  
2018 ◽  
Author(s):  
Guihao Chen ◽  
Yuejin Yang ◽  
Chuansheng Xu ◽  
Shuo Gao
Keyword(s):  
Flow Cytometry ◽  
Membrane Potential ◽  
Cardiac Myocytes ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Hypoxia Reoxygenation

Platelets apoptosis in rats after global brain ischemia

2018 ◽  
pp. 27-35
Author(s):  
А.А. Соколовская ◽  
Э.Д. Вирюс ◽  
В.В. Александрин ◽  
А.С. Роткина ◽  
К.А. Никифорова ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Ischemic Stroke ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Brain Ischemia ◽  
Mitochondrial Membrane ◽  
Male Rats ◽  
Global Brain Ischemia ◽  
Platelet Apoptosis ◽  
Global Brain

Цель исследования. Ишемические повреждения головного мозга, являются одной из наиболее частой причин инвалидности и смертности во всем мире. Недавно была установлена роль апоптоза тромбоцитов в патофизиологии инсульта, однако его механизмы до сих пор остаются невыясненными. Несмотря на различные экспериментальные модели, направленные на мониторинг апоптоза тромбоцитов, результаты, относительно изучения и выявления апоптоза тромбоцитов при ишемии головного мозга у крыс, весьма немногочисленны. Цель исследования - анализ апоптоза тромбоцитов с помощью метода проточной цитофлуориметрии на модели глобальной ишемии мозга у крыс. Методика. В экспериментах использовано 6 крыс-самцов Вистар в возрасте от 5 до 6 мес., разделенных на 2 группы: интактный контроль (К) и глобальная ишемия головного мозга. Модель глобальной ишемии головного мозга у крыс воспроизводилась путём билатеральной окклюзии общих сонных артерий на фоне гипотензии. Уровень системного артериального давления снижали посредством кровопотери до 40-45 мм рт. ст. Суспензию тромбоцитов крыс получали методом гельфильтрации с использованием сефарозы 2B. Для анализа экстернализации фосфатидилсерина (ФС) тромбоциты крыс инкубировали с Аннексином V-PE в связывающем буфере. Для оценки митохондриального мембранного потенциала (ММП) тромбоциты инкубировали с катионным красителем JC-1. После инкубации образцы немедленно анализировали на проточном цитофлуориметре FACSCalibur (Becton Dickinson, США). Результаты. Согласно полученным данным, экстернализация ФС на тромбоцитах крыс, перенесших инсульт, была значительно выше (53,45 ± 4,21%), чем в контрольной группе крыс (5,27 ± 2,40%). Данный эффект подтверждается выраженной деполяризацией митохондриальных мембран (DYm). После экспериментальной ишемии мозга почти 40% тромбоцитов было деполяризовано. Заключение. Использованный в работе подбор методов и маркеров обеспечивает понимание механизмов апоптоза тромбоцитов как в экспериментальных, так и в клинических условиях. Полученные данные позволяют сделать заключение, что апоптоз тромбоцитов является одним из факторов развития глобальной ишемии головного мозга у крыс. Результаты могут быть использованы для понимания механизмов, участвующих в развитии ишемического повреждения, что, в свою очередь, может быть использовано при разработке новых терапевтических стратегий. Aim. Stroke is one of the most common causes of disability and mortality worldwide. Multiple experimental models of stroke have focused on monitoring of platelet apoptosis. However, studies on and detection of platelet apoptosis in rats with ischemic stroke are very scarce. We investigated platelet apoptosis in rats with global brain ischemia using flow cytometry. Methods. Experiments were carried out on healthy, adult Wistar male rats weighing 300-350 g. The rats were divided into the following 2 groups: intact rats and rats with global brain ischemia. Global brain ischemia was induced by two-vessel (2-VO) carotid occlusion in combination with hypotension. Systemic blood pressure was reduced by 40-45 mm Hg by inducing haemorrhage. Platelets were isolated by gel filtration on Sepharose 2B. For evaluation of phosphatidylserine (PS) externalization, platelets were incubated with Annexin V-PE and analyzed on FACSCalibur (BD Biosciences). Mitochondrial membrane potential (DY) was measured during platelets apoptosis using JC-1, a mitochondrial membrane potential indicator. Platelets were analyzed by flow cytometry immediately after the incubation. Results. PS externalization on platelets was significantly greater after global brain ischemia (53.45 ± 4.21%) than in the control group (5.27 ± 2.40%). Pronounced depolarization of mitochondrial membrane potential (DYm) confirmed this finding. In the rat group with experimental brain ischemia, almost 40% (35.24 ± 5.21%) of platelets were depolarized. Conclusion. Our results provide insight into mechanisms involved in platelet apoptosis during ischemic stroke and can be used in further development of new therapeutic strategies.

Assessment of mitochondrial membrane potential in proximal tubules after hypoxia-reoxygenation

2005 ◽  
Vol 288 (6) ◽  
pp. F1092-F1102 ◽  
Author(s):  
Thorsten Feldkamp ◽  
Andreas Kribben ◽  
Joel M. Weinberg
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Atp Hydrolysis ◽  
Proximal Tubules ◽  
Green Fluorescence ◽  
Direct Assessment ◽  
Dynamic Studies ◽  
Safranin O ◽  
Hypoxia Reoxygenation

Proximal tubules develop a severe energetic deficit during hypoxia-reoxygenation (H/R) that previous studies using fluorescent potentiometric probes have suggested is characterized by sustained, partial mitochondrial deenergization. To validate the primary occurrence of mitochondrial deenergization in the process, optimize approaches for estimating changes in mitochondrial membrane potential (ΔΨm) in the system, and clarify the mechanisms for the defect, we further investigated the behavior of 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazocarbocyanine iodide (JC-1) in these cells and introduce a more dynamic and quantitative approach employing safranin O for use with the tubule system. Although use of JC-1 can be complicated by decreases in the plasma membrane potential that limit cellular uptake of JC-1 and such behavior was demonstrated in ouabain-treated tubules, changes in ΔΨm entirely accounted for the decreases in the formation of red fluorescent JC-1 aggregates and in the ratio of red/green fluorescence observed after H/R. The red JC-1 aggregates did not readily dissociate when tubules were deenergized after JC-1 uptake, making it unsuitable for dynamic studies of energization. Safranin O uptake by digitonin-permeabilized tubules required very small numbers of tubules, permitted measurements of ΔΨm for relatively prolonged periods after the end of the experimental maneuvers, was rapidly reversible during deenergization, and allowed for direct assessment of both substrate-dependent, electron transport-mediated ΔΨm, and ATP hydrolysis-supported ΔΨm. Both types of energization measured using safranin O in tubules permeabilized after H/R were impaired, but combining substrates and ATP substantially restored ΔΨm.

The Inhibitor of Cyclin-Dependent Kinase4a (INK4a) Signaling Pathway Induces Aging in Human Skeletal Muscle Myoblasts and Decreases the Mitochondrial Membrane Potential

2019 ◽  
Vol 9 (9) ◽  
pp. 1192-1198
Author(s):  
Dong Yan ◽  
Xiang Liao ◽  
Li-Xia Zhao ◽  
Chang-Hong Xiao
Keyword(s):  
Skeletal Muscle ◽  
Flow Cytometry ◽  
Membrane Potential ◽  
Signaling Pathway ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Human Skeletal Muscle ◽  
Lentiviral Vector ◽  
Accelerated Aging ◽  
Senescence Phenotype

The effect of the inhibitor of cyclin-dependent kinase4a (INK4a) signaling pathway on myoblastic aging was studied in this paper. Human skeletal muscle myoblasts were transfected with a recombinant lentiviral vector, pLVX-p16INK4a, encoding the p16INK4a gene, and RT-qPCR and western blotting were used to identify p16INK4a gene transcription and protein expression. The degree of cell senescence was assessed using Senescence-associated β-galactosidase staining. flow cytometry and JC-1 staining was used to analyze the mitochondrial membrane potential (MMP). The senescence phenotype was observed in myoblasts transfected with p16INK4a, the MMP was significantly decrease in p16INK4a-transfected myoblasts, while the MMP was decreased only slightly in control cells. Upregulation of the INK4a signaling pathway directly induced aging in human skeletal muscle myoblasts. Moreover, INK4a signaling pathway activated the mitochondrial pro-aging pathway by reducing the MMP, which indirectly accelerated aging in myoblasts.

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