Prolongation of bleeding time by acute hemolysis in rats: A role for nitric oxide

Tomasz Wollny, Licia Iacoviello, Wlodzimierz Buczko, Giovanni De Gaetano, Maria Benedetta Donati

Research output: Contribution to journalArticlepeer-review


The present study was aimed at clarifying the interaction between red blood cell trauma and bleeding observed in some clinical conditions. Acute hemolysis provoked by distilled water injection was followed by a significant prolongation of the 'template' bleeding time in rats. Comparable effects were observed after injection of an isotonic lysate of washed red blood cells. N(w)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) formation from L-arginine, normalized bleeding time when given to rats before hemolysis induction. The occurrence of hemolysis decreased ex vivo platelet adhesion to collagen without affecting platelet aggregation and induced a transient drop in blood pressure, the latter occurring during the first minute after injection. L-NAME pretreatment increased ex vivo platelet adhesion but did not affect either platelet aggregation or fall in blood pressure. All the effects of L-NAME were blunted by treating the animals with the NO precursor L-arginine but not o-arginine. Incubation of the erythrocyte lysate with apyrase prevented the prolongation of bleeding time induced by the hemolysate. Moreover, ADP administration, at doses that did not increase hemoglobin levels, induced effects similar to those observed after hemolysis (on template bleeding time and ex vivo platelet adhesion), which were also reversed by L-NAME and restored by L-arginine. ADP is abundantly released from (hemo)lysed red blood cells and is known to stimulate release of NO, a potent vasodilator and inhibitor of platelet adhesion. ADP-dependent NO release could be responsible for bleeding time prolongation, due to abnormalities in platelet-vessel wall interaction, during acute hemolysis. Lysis of white blood cells may also contribute to prolongation of bleeding time. Because ADP could not be detected in these cells, we postulate that other mechanisms also can be involved in bleeding time prolongation after blood cell activation in vivo.

Original languageEnglish
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number6 41-6
Publication statusPublished - 1997


  • Adenosine 5'-diphosphate
  • L-arginine
  • N(w)-nitro-L-arginine methyl ester
  • Platelet adhesion

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


Dive into the research topics of 'Prolongation of bleeding time by acute hemolysis in rats: A role for nitric oxide'. Together they form a unique fingerprint.

Cite this