title: Effects of supplementation of BH4 after prolonged ischemia in skeletal muscle.
abstract: OBJECTIVE
  To determine whether the supplementation of tetrahydrobiopterin (BH(4), an essential cofactor of nitric oxide synthase; NOS) could attenuate endothelial dysfunction and improve NOS activity and cell viability in skeletal muscle after ischemia/reperfusion (I/R).
  
  
  METHODS
  A vascular pedicle isolated rat cremaster muscle model was used. Cremaster muscles were subjected to 4 h of ischemia followed by 2 h of reperfusion. Rats were given either normal saline or BH(4) by intravenous injection at 1 min prior to reperfusion. After reperfusion, average arteriole diameter, capillary perfusion, endothelial-dependent/-independent vasodilatation, NOS activity, and muscle cell viability were evaluated.
  
  
  RESULTS
  Supplementation of BH(4) prior to reperfusion significantly attenuated reperfusion-induced vasoconstriction, poor capillary perfusion, and endothelial dysfunction and enhanced cNOS activity and slightly improved cell viability in the skeletal muscle after I/R.
  
  
  CONCLUSIONS
  Supplementation of BH(4) during reperfusion provided a significant protection against I/R injury in rat skeletal muscle.
authors.affiliation: Division of Plastic Surgery, Department of Surgery, University of Nevada School of Medicine, Las Vegas, NV 89102, USA. wzwang2000@yahoo.com
authors.forename: Wei Z
authors.initials: WZ
authors.lastname: Wang
authors.forename: Xin-Hua
authors.initials: XH
authors.lastname: Fang
authors.forename: Linda L
authors.initials: LL
authors.lastname: Stephenson
authors.forename: Kayvan T
authors.initials: KT
authors.lastname: Khiabani
authors.forename: William A
authors.initials: WA
authors.lastname: Zamboni
mesh_terms: D000818:Animals; D001708:Biopterins / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D002470:Cell Survival; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D007275:Injections, Intravenous; D008297:Male; D008833:Microcirculation; D018482:Muscle, Skeletal / Q000098:blood supply*; D019001:Nitric Oxide Synthase / Q000008:administration & dosage* / Q000378:metabolism / Q000627:therapeutic use; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000503:physiopathology*; D014664:Vasodilation / Q000187:drug effects
chemical_list: D001708:Biopterins; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C003402:sapropterin