Effects of Intermittent Exercise on Calcium Transient and Systolic Function of Single Myocardial Cells in Infarcted Area of Rats with Myocardial Infarction

  • Xiaofeng Zhu
Keywords: Intermittent Exercise, Myocardial Infarction, Cellular Calcium Transient, Systolic Function

Abstract

The purpose of this study was to investigate the effects of intermittent exercise on calcium transient
and systolic function in single myocardial cells in the peri-infarct region of rats, as well as the role of time
window and its role in exercise inhibition of cardiomyocyte apoptosis. The effective means and methods of stalk
disease provide new ideas, new targets and experimental basis. By using rats, 45 male SD rats aged 3 months.
All rats were fed for seven days in the same feeding environment, and then 15 rats in each group were divided
into surgery group (S), myocardial infarction group (MI), myocardial infarction + exercise group (ME). The
central infarction group was ligated to the left anterior descending coronary artery to prepare the myocardial
infarction model; the surgical group was treated with no threading; the myocardial infarction + exercise group
needed to start intermittent movement after seven days after surgery. The main content of the exercise included
seven days of adaptation. Intermittent exercise (15m/min×20min/d), then exercise 10m/min×10min, then
exercises 15m/min×6min and 25m/min×4min, weekly intermittent exercise for five days for 7 weeks. On the
next day after the completion of the training, the cardiomyocytes were anesthetized and isolated, and the
myocardial single cells were measured by Ion Optix [Ca2+]i amplitude, [Ca2+]i fluorescence ratio (Ratio),
Departure velocity, TTP, Calcium transients such as TTP 50%, TTB 50%, Return velocity, and Ratio amplitude,
and individual myocardial contractile function factors such as ±dl/dtmax, SL, PTA, and SL shortening.
Experiments show that intermittent exercise can stimulate the increase of NRG1 level in rat myocardium,
activate NRGl-SERCA2a pathway and enhance cardiac function; Exogenous NRG1 and intermittent exercise
can significantly enhance calcium transients in rat cardiomyocytes, thereby increasing their contractility;
Myocardial infarction caused abnormal calcium regulation in single cardiomyocytes, and the amplitude and rate
of calcium transients were significantly decreased, which impaired the contractile ability of single
cardiomyocytes. Intermittent exercise can simultaneously improve the calcium transient of myocardial viable
cells in the infarcted area of rats with myocardial infarction.

Published
2019-11-01