Ischemic preconditioning improves oxygenation of exercising muscle in vivo.
BACKGROUND
Ischemic preconditioning (IP) improves tissue tolerance to prolonged ischemia. In this study, we investigated the functional effect of IP on skeletal muscle of rat hind limb by means of near-infrared spectroscopy (NIRS) and by measuring myeloperoxidase (MPO) activity.


METHODS
Adult male Sprague Dawley rats were divided into four separate protocol groups according to different preparations prior to 2 h of global ischemia: a group of ischemic reperfusion without any preparation (I/R), ischemic reperfusion with ischemic preconditioning (IP+IR), ischemic reperfusion with adenosine infusion (ADO+I/R), and sham operation. Ischemia and ischemic preconditioning were induced by clamping infrarenal abdominal aorta and left common iliac artery. For each rat, an exercise test of gastrocnemius muscles was performed by stimulating sciatic nerve before and after global ischemia while performing NIRS. MPO activity of ischemic muscles was also measured.


RESULTS
Half-resaturation time after exercise and MPO activity were significantly improved in IP+IR and ADO+I/R groups. Difference of oxyhemoglobin during exercise was also improved in the IP+IR group.


CONCLUSIONS
This study has demonstrated that IP provides the protective effect on in vivo skeletal muscle oxygenation during exercise.
Saito
Taketo
T
Department of Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan. taketo@sage.ocn.ne.jp
Komiyama
Takashi
T
Aramoto
Haruo
H
Miyata
Tetsuro
T
Shigematsu
Hiroshi
H
D000818:Animals; D019069:Cell Respiration / Q000502:physiology*; D006614:Hindlimb; D019194:Ischemic Preconditioning / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000379:methods; D051381:Rats; D019265:Spectroscopy, Near-Infrared / Q000379:methods
D009195:Peroxidase; D010100:Oxygen