Physiological Adaptations to Progressive Endurance Exercise Training in Adult and Aged Rats: Insights from the Molecular Transducers of Physical Activity Consortium (MoTrPAC)
Authors: Schenk Simon , Sagendorf Tyler J , Many Gina M , Lira Ana K , de Sousa Luis G O , Bae Dam , Cicha Michael , Kramer Kyle S , Muehlbauer Michael , Hevener Andrea L , Rector R Scott , Thyfault John P , Williams John P , Goodyear Laurie J , Esser Karyn A , Newgard Christopher B , Bodine Sue C ,   The MoTrPAC Study Group, Adkins Joshua N , Albertson Brent G , Amar David , Amper Mary Anne S , Ashley Euan , Bae Dam , Bamman Marcas M , Barnes Jerry , Bergman Bryan C , Bessesen Daniel H , Bodine Sue C , Buford Thomas W , Burant Charles F , Cicha Michael , Cutter Gary R , De Sousa Luis Gustavo Oliveria , Esser Karyn A , Fernández Facundo M , Gaul David A , Ge Yongchao , Goodpaster Bret H , Goodyear Laurie J , Guevara Kristy , Hevener Andrea L , Hirshman Michael F , Huffman Kim M , Jackson Bailey E , Jankowski Catherine M , Jimenez-Morales David , Kohrt Wendy M , Kramer Kyle S , Kraus William E , Lessard Sarah J , Lester Bridget , Lindholm Malene E , Lira Ana K , Many Gina , Marjanovic Nada , Marshall Andrea G , Melanson Edward L , Miller Michael E , Moreau Kerrie L , Nair Venugopalan D , Newgard Christopher B , Ortlund Eric A , Qian Wei-Jun , Rasmussen Blake B , Rector R Scott , Richards Collyn Z-T , Rushing Scott , Sagendorf Tyler J , Sanford James A , Schauer Irene E , Schenk Simon , Schwartz Robert S , Sealfon Stuart C , Seenarine Nitish , Sparks Lauren M , Stowe Cynthia L , Talton Jennifer W , Teng Christopher , Tesfa Nathan D , Thalacker-Mercer Anna , Thyfault John P , Trappe Scott , Trappe Todd A , Vasoya Mital , Wheeler Matthew T , Walkup Michael P , Williams John P , Yan Zhen , Zhen Jimmy 
Published: March 2024

Abstract
While regular physical activity is a cornerstone of health, wellness, and vitality, the impact of endurance exercise training on molecular signaling within and across tissues remains to be delineated. The Molecular Transducers of Physical Activity Consortium (MoTrPAC) was established to characterize molecular networks underlying the adaptive response to exercise. Here, we describe the endurance exercise training studies undertaken by the Preclinical Animal Sites Studies component of MoTrPAC, in which we sought to develop and implement a standardized endurance exercise protocol in a large cohort of rats. To this end, Adult (6-mo) and Aged (18-mo) female (n = 151) and male (n = 143) Fischer 344 rats were subjected to progressive treadmill training (5 d/wk, ∼70%–75% VO2max) for 1, 2, 4, or 8 wk; sedentary rats were studied as the control group. A total of 18 solid tissues, as well as blood, plasma, and feces, were collected to establish a publicly accessible biorepository and for extensive omics-based analyses by MoTrPAC. Treadmill training was highly effective, with robust improvements in skeletal muscle citrate synthase activity in as little as 1–2 wk and improvements in maximum run speed and maximal oxygen uptake by 4–8 wk. For body mass and composition, notable age- and sex-dependent responses were observed. This work in mature, treadmill-trained rats represents the most comprehensive and publicly accessible tissue biorepository, to date, and provides an unprecedented resource for studying temporal-, sex-, and age-specific responses to endurance exercise training in a preclinical rat model.