title: Redistribution of labile plasma zinc during mild surgical stress in the rat.
abstract: Zinc is an essential trace element and cofactor for many cellular processes. Uptake of ionized divalent zinc (Zn(2+)) in peripheral tissues depends on its total content in the circulation and on mechanisms facilitating delivery to tissues in its labile form. Understanding mechanisms of Zn(2+) delivery has been hindered by the absence of techniques to detect labile Zn(2+) in the circulation. In this study, we report the use of the fluorescent zinc-binding dye (ZnAF-2) to detect changes in labile Zn(2+) in the circulating plasma of the rat under standardized conditions, including exogenous infusions to increase plasma Zn(2+) and an infusion of the chelator, citrate, to decrease labile Zn(2+) in the plasma without altering total Zn(2+) content. In a model of mild surgical stress (unilateral femoral arterial ligation), plasma levels of total and labile Zn(2+) decreased significantly 24 h after the operation. Ultrafiltration of plasma into high- and low-molecular weight macromolecule fractionations indicated that binding capacity of zinc in the high-molecular weight fraction is impaired for the entire 24-h interval after induction of mild surgical stress. Affinity of the filtrate fraction was rapidly and reversibly responsive to anesthesia alone, decreasing significantly at 4 h and recovering at 24 h; in animals subjected to moderate surgical stress, this responsiveness was lost. These findings are the first reported measurements of labile Zn(2+) in the circulation in any form of mild systemic stress. Zinc undergoes substantial redistribution in the plasma as a response to surgical stress, leading to increased availability in lower molecular weight fractions and in its labile form.
authors.affiliation: Division of General and Gastrointestinal Surgery, Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02118, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Kelly
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Mathew
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Kohler
authors.forename: Amy L
authors.initials: AL
authors.lastname: Blass
authors.forename: David I
authors.initials: DI
authors.lastname: Soybel
mesh_terms: D000818:Animals; D002413:Cations, Divalent / Q000008:administration & dosage / Q000097:blood; D002614:Chelating Agents / Q000008:administration & dosage; D019343:Citric Acid / Q000008:administration & dosage; D005456:Fluorescent Dyes / Q000008:administration & dosage; D007262:Infusions, Intravenous; D017136:Ion Transport; D008297:Male; D023421:Models, Animal; D011725:Pyridines / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D013312:Stress, Physiological / Q000502:physiology; D013514:Surgical Procedures, Operative / Q000009:adverse effects; D014131:Trace Elements / Q000008:administration & dosage / Q000097:blood; D015032:Zinc / Q000008:administration & dosage / Q000097:blood*
chemical_list: D002413:Cations, Divalent; D002614:Chelating Agents; D005456:Fluorescent Dyes; D011725:Pyridines; D014131:Trace Elements; C462061:ZnAF-2; D019343:Citric Acid; D015032:Zinc