Training/detraining-induced gender specific functional adaptations of isolated rat heart

Abstract

Background/Aim. While the mechanisms responsible for the beneficial effects of aerobic exercise training on cardiovascular function are well known, detraining effects on myocardial parameters has not been adequately elucidated. Therefore, the study aimed to determine the occurrence and speed of cardiac adaptation reversibility after the cessation of aerobic exercise, and also to reveal gender differences in achieved effects of training/detraining. Methods. Female and male Wistar albino rats were divided into following groups: control, trained and two detrained groups. Hearts were perfused according to Langendorff technique and cardiodynamic parameters: maximum and minimum rate of pressure development in the left ventricle (dp/dt max, dp/dt min), systolic and diastolic left ventricular pressure (SLVP, DLVP), heart rate (HR) and coronary flow were determined. Results.Training significantly reduced values of dp/dt max, dp/dt min and SLVP in males and females and coronary flow in males. Detraining caused reversion of those changes, which was gender specific. In females, levels of SLVP were higher after 4 weeks of detraining than training and 2 weeks of detraining. Values of SLVP were lower in both detraining periods compared to training in males. While males had higher coronary flow after 2 weeks of detraining, it was reduced in the 4 th week of detraining in females. Conclusion:Present study by using a model of the isolated rat heart confirmed existence of traininginduced changes in cardiac function. Cessation of training was followed by the loss of those adaptations, faster in males than females. Apstrakt Uvod/Cilj. Dok su mehanizmi odgovorni za blagotvorno dejstvo aerobnog treninga na funkciju kardiovaskularnog sistema dobro poznati, efekti detreninga na parametre srčane funkcije nisu dovoljno razjašnjeni. Studija je imala za cilj da utvrdi pojavu i brzinu reverzibilnosti srčane adaptacije nakon prestanka aerobnog treninga, kao i da otkrije postojanje razlike među polovima prilikom treninga/detreninga. Metode. Wistar albino pacovi (ženke i mužjaci) su svrstani u sledeće grupe: kontrolna, trening i dve detrening grupe.Izolovana srca su perfundovana po Langendorff tehnici pri čemu su praćeni sledeći kardiodinamski parametri: maksimalna i minimalna stopa razvoja pritiska u levoj komori (dp/dt max, dp/dt min), sistolni i dijastolni pritisak u levoj komori (SLVP, DLVP), frekvenca srca (HR) i koronarni protok. Rezultati. Trening je značajno smanjio vrednosti dp/dt max, dp/dt min i SLVP kod mužjaka i ženki kao i koronarni protok kod mužjaka. Detrening je doveo do polno zavisnog vraćanja vrednosti postignutih tokom treninga. Kod ženki, nivo SLVP je bio viši nakon 4 nedelje detreninga nego u treningu i 2 nedelje detreninga. Vrednosti SLVP su bile niže u oba perioda detreninga u poređenju sa treningom kod mužjaka. Mužjaci su imali veće vrednosti koronarnog protoka nakon 2 nedelje detreninga dok se koronarni protok smanjio u 4 nedelji detreninga kod ženki. Zaključak. Ovim istraživanjem smo na modelu izolovanog srca pacova po...