Interactive Effects of Enalapril Administration and Novel HIIT Wheel-Bed Training in Aged Rats.

Youfeng Yang,Anisha Banerjee,Thomas W Buford,Yi Sun,Christy S Carter

doi:10.3389/fresc.2021.764686

Abstract

Introduction:Growing research suggests that aerobic high-intensity interval training (HIIT) improves cardiovascular function and physical performance compared with moderate intensity continuous training (MICT). However relatively few animal models of HIIT are available to inform about the benefits of this exercise—particularly among older animals. In addition, there is little evidence for how HIIT training interacts with adjuvant pharmacological therapies known to enhance the impact of MCIT in older individuals such as Angiotensin Converting Enzyme (ACE) Inhibitors.Purpose:The aim of the present study was to establish a HIIT protocol in aged rats based on forced running wheel-bed, and to subsequently (1) establish the feasibility of the HIIT protocol in a proof-of-concept study evaluating interactions between HIIT and (2) the result of combining HIIT + ACE inhibitor treatment using the ACE inhibitor enalapril.Methods:Two groups of rats were used in this study. The feasibility of using wheel-bed for HIIT training was tested in group one (15- and 30-month-old male rats). In the second group, 37 24-month-old Fisher 344 × Brown Norway male rats were randomly divided into four subgroups: control, enalapril, HIIT training group, and HIIT training combined with enalapril administration. The training and administration lasted for 4 weeks. After the intervention, locomotor activity, exercise tolerance, and grip strength were tested.Results:Our feasibility study suggested that middle-aged and aged rats were able to successfully complete the HIIT training. In our intervention study, HIIT training alone, regardless of adjuvant enalapril intervention, did raise treadmill exercise tolerance vs. the sedentary condition. Measures of healthspan were not negatively impacted by HIIT training.Conclusion:The novel HIIT protocol based on forced running wheel-bed was successfully employed in aged rats. We conclude that future studies should compare the results and of multi-modal intervention strategies which include both HIIT and MICT in combination with adjuvant therapies such as enalapril to improve exercise tolerance and other global indices of healthspan.

Highlights

Growing research suggests that aerobic high-intensity interval training (HIIT) improves cardiovascular function and physical performance compared with moderate intensity continuous training (MICT)
The purpose of this study is to develop a rat HIIT protocol based on the forced running wheel-bed
We evaluated the interaction of HIIT with enalapril treatment, a commonly used pharmacologic agent with which our laboratory has extensive experience

Summary

Introduction

Growing research suggests that aerobic high-intensity interval training (HIIT) improves cardiovascular function and physical performance compared with moderate intensity continuous training (MICT). There is little evidence for how HIIT training interacts with adjuvant pharmacological therapies known to enhance the impact of MCIT in older individuals such as Angiotensin Converting Enzyme (ACE) Inhibitors. Moderateintensity continuous training (MICT) has been the most preferred exercise modality for improving body composition and cardiorespiratory fitness [4]. HIIT is undoubtedly a time-efficient strategy to increase metabolism and enhance skeletal muscle capacity [3, 6]. Aerobically-based HIIT has been reported to extensively improve cardiorespiratory fitness—a strong determinant of morbidity and mortality [5]—and to stimulate an increase of serum brain-derived neurotrophic factor (BDNF) concentrations—a critical indicator for mental health [9]. Aerobic HIIT leads to mitochondrial biogenesis and induces multiple factors involved in tissue regeneration [10, 11]

Objectives

Methods

Results

Conclusion