Exercise-enhanced satellite cell proliferation and new myonuclear accretion in rat skeletal muscle

Heather K. Smith, Linda Maxwell, Carol D. Rodgers, Nancy H. McKee, Michael J. Plyley
2001 Journal of applied physiology  
Exercise-enhanced satellite cell proliferation and new myonuclear accretion in rat skeletal muscle. J Appl Physiol 90: [1407][1408][1409][1410][1411][1412][1413][1414] 2001.-The effects of increased functional loading on early cellular regenerative events after exercise-induced injury in adult skeletal muscle were examined with the use of in vivo labeling of replicating myofiber nuclei and immunocyto-and histochemical techniques. Satellite cell proliferation in the soleus (Sol) of nonexercised
more » ... l) of nonexercised rats (0.4 Ϯ 0.2% of fibers) was unchanged after an initial bout of declined treadmill exercise but was elevated after two (1.0 Ϯ 0.2%, P Յ 0.01), but not four or seven, daily bouts of the same task. Myonuclei produced over the 7-day period comprised 0.9-1.9% of myonuclei in isolated fibers of Sol, tibialis anterior, and vastus intermedius of nonexercised rats. The accretion of new myonuclei was enhanced (P Յ 0.05) in Sol and vastus intermedius by the initial exercise followed by normal activity (to 3.1-3.4% of myonuclei) and more so by continued daily exercise (4.2-5.3%). Observed coincident with a lower incidence of histological fiber injury and unchanged fiber diameter and myonuclei per millimeter, the greater new myonuclear accretion induced by continued muscle loading may contribute to an enhanced fiber repair and regeneration after exerciseinduced injury. eccentrically biased exercise; muscle injury; immunocytochemistry; fiber type; bromodeoxyuridine
doi:10.1152/jappl.2001.90.4.1407 pmid:11247941 fatcat:ep22snfgjbc3deylz6pbbtnkey