Platelet thrombus formation and hemostasis are delayed in the microcirculation of copper-deficient rats.
The role of dietary copper in platelet thrombus formation and hemostasis was studied in the cremaster muscle microcirculation. Male weanling Sprague-Dawley rats were fed purified diets that were either copper-adequate (94 mumol Cu/kg diet) or copper-deficient (0 mumol Cu/kg diet) for 1, 3 or 5 wk. The rats were anesthetized with pentobarbital, and the cremaster was spread in a Krebs-filled tissue bath. Fluorescein isothiocyanate tagged to bovine serum albumin (FITC-BSA) was injected intra-arterially. After a 20-min equilibration, blue light (1.8 W/cm2, 450-490 nm) was used to activate the FITC-BSA and induced platelet thrombus formation within the vasculature. In vivo television microscopy was used to quantify the thrombus formation. In rats fed the copper-deficient diet for 3 or 5 wk, platelet thrombus formation induced by photoactivation was significantly (P < 0.05) delayed and prothrombin time was significantly longer but the number of circulating platelets was significantly greater than in age-matched rats fed the copper-adequate diet. Bleeding time, measured after micropuncture of a second-order venule, was significantly longer but hematocrit was significantly lower in rats fed the copper-deficient diet than in those fed the copper-adequate diet. The results demonstrate that platelet-mediated hemostasis is depressed in dietary copper deficiency and that this may be due to a decrease in hematocrit, a decrease in the activity of a coagulation factor and/or an alteration of platelet function.
Schuschke
D A
DA
Center for Applied Microcirculatory Research, University of Louisville, KY 40292.
Saari
J T
JT
Nuss
J W
JW
Miller
F N
FN
D000818:Animals; D001760:Bleeding Time; D001792:Blood Platelets / Q000502:physiology*; D003300:Copper / Q000008:administration & dosage / Q000172:deficiency* / Q000502:physiology; D004032:Diet; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000494:pharmacology; D006400:Hematocrit; D006487:Hemostasis; D008297:Male; D008833:Microcirculation / Q000503:physiopathology*; D010777:Photochemistry; D010976:Platelet Count; D011517:Prothrombin Time; D051381:Rats; D017207:Rats, Sprague-Dawley; D012710:Serum Albumin, Bovine / Q000494:pharmacology
C039217:fluorescein isothiocyanate bovine serum albumin; D012710:Serum Albumin, Bovine; D003300:Copper; D016650:Fluorescein-5-isothiocyanate