Pulmonary hypertension due to monocrotaline pyrrole is reduced by moderate thrombocytopenia

Am J Physiol. 1988 Nov;255(5 Pt 2):H1165-72. doi: 10.1152/ajpheart.1988.255.5.H1165.


To elucidate further the role of the platelet in the development of monocrotaline pyrrole (MCTP)-induced lung injury and pulmonary hypertension, MCTP-treated rats were made thrombocytopenic by cotreatment with an anti-rat platelet serum (PAS). Lung injury was assessed from increases in lung weight, lavage fluid protein concentration, and lactate dehydrogenase activity and from accumulation in lung tissue of 125I-labeled albumin. These indexes of injury were not different in MCTP-treated rats with normal or reduced platelet numbers at day 4,8, or 14. In MCTP-treated rats not receiving the PAS, pulmonary arterial pressure was elevated by day 8. However, pulmonary arterial pressure was the same as controls at both day 8 and day 14 in MCTP-treated rats made moderately thrombocytopenic by cotreatment with PAS. More marked reduction of platelet number abolished the protective effect of thrombocytopenia against pulmonary hypertension. In a separate series of experiments, treatment with antibodies to platelet-derived growth factor (PDGF), a potential mediator in the response to MCTP-induced injury, did not protect rats from the cardiopulmonary effects of MCTP. These data indicate that moderate reduction of the number of circulating platelets prevents MCTP-induced pulmonary hypertension but not MCTP-induced lung injury, suggesting that the platelet is involved in the pulmonary hypertensive response to MCTP-induced lung injury by unknown mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blood Platelets / physiology*
  • Blood Pressure
  • Hypertension, Pulmonary / chemically induced*
  • Hypertension, Pulmonary / complications
  • Hypertension, Pulmonary / physiopathology
  • Immunization, Passive
  • L-Lactate Dehydrogenase / metabolism
  • Male
  • Monocrotaline* / analogs & derivatives*
  • Platelet-Derived Growth Factor / immunology
  • Platelet-Derived Growth Factor / physiology
  • Pyrrolizidine Alkaloids*
  • Rats
  • Rats, Inbred Strains
  • Thrombocytopenia / complications
  • Thrombocytopenia / physiopathology*


  • Platelet-Derived Growth Factor
  • Pyrrolizidine Alkaloids
  • monocrotaline pyrrole
  • Monocrotaline
  • L-Lactate Dehydrogenase