Exercise-induced metallothionein expression in human skeletal muscle fibres

TY - JOUR

T1 - Exercise-induced metallothionein expression in human skeletal muscle fibres

AU - Penkowa, Milena

AU - Keller, Pernille

AU - Keller, Charlotte

AU - Hidalgo, Juan

AU - Giralt, Mercedes

AU - Pedersen, Bente Klarlund

N1 - Keywords: Adult; Exercise; Exercise Test; Humans; Immunohistochemistry; Male; Metallothionein; Muscle Fibers, Skeletal; Muscle Proteins; Muscle, Skeletal; Oxidative Stress; RNA, Messenger; Reverse Transcriptase Polymerase Chain Reaction

PY - 2005

Y1 - 2005

N2 - Exercise induces free oxygen radicals that cause oxidative stress, and metallothioneins (MTs) are increased in states of oxidative stress and possess anti-apoptotic effects. We therefore studied expression of the antioxidant factors metallothionein I and II (MT-I + II) in muscle biopsies obtained in response to 3 h of bicycle exercise performed by healthy men and in resting controls. Both MT-I + II proteins and MT-II mRNA expression increased significantly in both type I and II muscle fibres after exercise. Moreover, 24 h after exercise the levels of MT-II mRNA and MT-I + II proteins were still highly increased and the MT-II mRNA expression reached a 15-fold increase. As expected, immunohistochemical detection of malondialdehyde (MDA) and nitrotyrosine (NITT) showed that formation of free radicals and oxidative stress were clearly increased in exercising muscle peaking shortly after the end of exercise in both type I and II muscle fibres. This is the first report demonstrating that MT-I + II are significantly induced in human skeletal muscle fibres following exercise. As MT-I + II are antioxidant factors that protect various tissues during pathological conditions, the MT-I + II increases post exercise may represent a mechanism whereby contracting muscle fibres are protected against cellular stress and injury.

AB - Exercise induces free oxygen radicals that cause oxidative stress, and metallothioneins (MTs) are increased in states of oxidative stress and possess anti-apoptotic effects. We therefore studied expression of the antioxidant factors metallothionein I and II (MT-I + II) in muscle biopsies obtained in response to 3 h of bicycle exercise performed by healthy men and in resting controls. Both MT-I + II proteins and MT-II mRNA expression increased significantly in both type I and II muscle fibres after exercise. Moreover, 24 h after exercise the levels of MT-II mRNA and MT-I + II proteins were still highly increased and the MT-II mRNA expression reached a 15-fold increase. As expected, immunohistochemical detection of malondialdehyde (MDA) and nitrotyrosine (NITT) showed that formation of free radicals and oxidative stress were clearly increased in exercising muscle peaking shortly after the end of exercise in both type I and II muscle fibres. This is the first report demonstrating that MT-I + II are significantly induced in human skeletal muscle fibres following exercise. As MT-I + II are antioxidant factors that protect various tissues during pathological conditions, the MT-I + II increases post exercise may represent a mechanism whereby contracting muscle fibres are protected against cellular stress and injury.

U2 - 10.1113/expphysiol.2004.029371

DO - 10.1113/expphysiol.2004.029371

M3 - Journal article

C2 - 15640275

SN - 0958-0670

VL - 90

SP - 477

EP - 486

JO - Experimental Physiology

JF - Experimental Physiology

IS - 4

ER -