title: Effect of cold on ischemia--reperfusion-induced microvascular permeability increase in cat skeletal muscle.
abstract: The effects of reduced temperature during ischemia (I) upon microvascular permeability and resistance increases during reperfusion (R) were assessed in skeletal muscle. Protein solvent-drag reflection coefficients (sigma f) and changes in vascular resistance were measured during 37 degrees C reperfusion of isolated, whole-blood perfused cat hindlimbs after the limbs had been subjected to 3.5 h of ischemia at several temperatures. sigma f was determined from the disappearance rates of water and protein from the circulating perfusate during a period of induced microvascular fluid filtration. The I/R procedure at 37 degrees C caused sigma f to fall from approximately 0.85 to approximately 0.5, indicating a large increase in microvascular permeability. Hypothermic ischemia at 30, 22, 17, or 12 degrees C totally abolished this drop in sigma f. However, when the ischemia was at approximately 5 degrees C, there was a significant fall in sigma f to approximately 0.7, which was similar to the value we found previously with 5 h of continuous perfusion at this low temperature. The normothermic I/R procedure led to an increase in vascular resistance of approximately 250% above the value measured prior to I/R. Hypothermic ischemia totally abolished this resistance increase, except for the lowest temperature, for which the increase was 150%. Therefore, hypothermia can prevent the microvascular dysfunction caused by 3.5 h of ischemia at 37 degrees C in this preparation. However, when the temperature was reduced too far (approximately 5 degrees C), a cold injury to the microvascular resulted in permeability and resistance increases.
authors.affiliation: Division of Pediatric Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
authors.forename: J X
authors.initials: JX
authors.lastname: Zhang
authors.forename: M B
authors.initials: MB
authors.lastname: Wolf
mesh_terms: D000818:Animals; D002199:Capillary Permeability / Q000502:physiology*; D002415:Cats; D003080:Cold Temperature; D005260:Female; D006614:Hindlimb; D066298:In Vitro Techniques; D008297:Male; D009132:Muscles / Q000098:blood supply* / Q000293:injuries* / Q000503:physiopathology; D010477:Perfusion; D015427:Reperfusion Injury / Q000503:physiopathology / Q000517:prevention & control*; D013696:Temperature; D013997:Time Factors; D014655:Vascular Resistance / Q000502:physiology