Exercise‐induced heart mitochondrial cholesterol depletion influences the inhibition of mitochondrial swelling. Issue 10 (24th July 2013)

• Record Type: Journal Article
• Authors: Ziolkowski, Wieslaw; Vadhana MS, Dhivya; Kaczor, Jan Jacek; Olek, Robert Antoni; Flis, Damian Jozef; Halon, Malgorzata; Wozniak, Michal; Fedeli, Donatella; Carloni, Manuel; Antosiewicz, Jedrzej; Gabbianelli, Rosita
• Is Part Of: Experimental physiology. Volume 98:Issue 10(2013:Oct.)
• Page Start: 1457
• Page End: 1468
• Publication Date: 2013-07-24
• Subjects: Physiology, Experimental -- Periodicals; 571.0724
• DOI: 10.1113/expphysiol.2013.073007
• Languages: English
• ISSNs: 0958-0670

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>New findings</title> <p> <list id="l1" list-type="simple"> <list-item> <label> </label> <p> <bold>What is the central question of this study?</bold> </p> <p>The central question was to establish whether decreased cholesterol content in heart mitochondria caused by prolonged swimming may provoke changes in their bioenergetics and affect resistance to CaCl<sub>2</sub>‐induced mitochondrial swelling.</p> </list-item> <list-item> <label> </label> <p> <bold>What is the main finding and its importance?</bold> </p> <p>The main finding is the indication that changes in the cholesterol pool in heart mitochondria induced by swimming exercise are related to an increase in resistance to CaCl<sub>2</sub>‐induced swelling, probably by remodelling of lipid microdomains, and are not deleterious for mitochondrial bioenergetics. These findings may contribute to a more complete understanding of the defense system that may prevent mitochondrial degradation during exercise and the protective system of cardiac cell defense in stress conditions.</p> </list-item> </list> </p> <p>The significance of the reduction of the cholesterol pool in heart mitochondria after exercise is still unknown. Recently, published data have suggested that cholesterol may influence the components of mitochondrial contact site and affect mitochondrial swelling. Therefore, the aim of this study was to determine whether the decreased cholesterol content in heart mitochondria caused by prolonged swimming may provoke changes in their bioenergetics and result in an increased resistance to calcium chloride‐induced mitochondrial swelling. Male Wistar rats were divided into a sedentary control group and an exercise group. The rats exercised for 3 h, burdened with an additional 3% of their body weight. Their hearts were removed immediately after completing the exercise. The left ventricle was divided and used for experiments. Mitochondrial cholesterol content, membrane fluidity and mitochondrial bioenergetics were measured in the control and exercised rat heart mitochondria. To assess whether mitochondrial modifications are linked to disruption of lipid microdomains, methyl‐β‐cyclodextrin, a well‐known lipid microdomain‐disrupting agent and cholesterol chelator, was applied to the mitochondria of the control group. Cholesterol depletion, increased membrane fluidity and increased resistance to calcium chloride‐induced swelling were observed in postexercise heart crude mitochondrial fraction. Similar results were achieved in control mitochondria treated with 2% methyl‐β‐cyclodextrin. All of the mitochondrial bioenergetics parameters were similar between the groups. Therefore, the disruption of raft‐like microdomains appears to be an adaptive change in the rat heart following exercise.</p> </abstract>