Sex-related beneficial effects of exercise on cardiac function and rhythm in autistic rats

Abstract

Background: Cardiovascular diseases are prevalent in autistic patients. As exercise is useful in the treatment of medical conditions, this study aimed to identify the effect of low-intensity endurance exercise (LIEE) and moderate-intensity endurance exercise (MIEE) on cardiovascular events in autistic rats.

Methods: Valproic acid (VPA) was administrated once on gestational day 12.5 to pregnant rats to produce autism-like symptoms in offspring. Thirty-day-old offspring were divided into 12 groups: Male-CTL, Male-VPA, Male-CTL + LIEE, Male-CTL + MIEE, Male-VPA + LIEE, Male-VPA + MIEE, Female-CTL, Female-VPA, Female-CTL + LIEE, Female-CTL + MIEE, Female-VPA + LIEE, and Female-VPA + MIEE. LIEE and MIEE were performed 5 days a week for 30 days. Twenty-four hours after the last exercise session, electrocardiogram and hemodynamic and cardiac function indices were recorded.

Results: The results indicated that +dp/dt max and contractility index (CI) decreased in the Female-VPA group compared to the Female-CTL group. LIEE increased these parameters in the Female-VPA + LIEE group. However, MIEE normalized CI in the Male-VPA + MIEE compared to the Male-VPA group. Tau increased in the Female-VPA group compared to the Female-CTL group and it decreased in the Female-VPA + MIEE group compared to the Female-VPA group. LIEE and MIEE recovered the reduction of heart rate and the increase in P, R, and T amplitudes in Male-VPA group. LIEE and MIEE increased heart rate variability in the Male-VPA and Female-VPA groups.

Conclusions: The findings showed that LIEE and MIEE alleviated cardiac dysfunction and disturbances in heart rhythm in the autistic offspring. Exercise may be recommended as a routine program for autistic patients to prevent and treat the harmful cardiovascular consequences of autism.

Keywords: arrhythmias; autism; contractility; exercise; heart function; heart rate variability.