Journal of Applied Physiology, Vol 55, Issue 5 1480-1485, Copyright © 1983 by American Physiological Society
Effect of complement depletion on lung fluid balance after thrombin
A. Johnson, F. A. Blumenstock and A. B. Malik
We examined the effect of complement depletion on lung fluid and protein
exchange after thrombin-induced pulmonary thromboembolization. Sheep were
prepared with lung lymph fistulas to assess pulmonary transvascular fluid
and protein dynamics. Studies were made in three groups: in group I (n = 5)
pulmonary thromboembolization (PT) was induced by an iv infusion of
thrombin (55.0 +/- 12.9 NIH U/kg); in group II (n = 6) cobra venom factor
(CVF) was given ip (94.5 +/- 18.8 U/kg/day) for 2 days to deplete
complement, and then thrombin (66.4 +/- 37.0 NIH U/kg) was infused to raise
pulmonary vascular resistance to the same level as in group I; in group III
(n = 10) left atrial pressure (Pla) was increased by 10-15 Torr in normal
animals by inflation of a Foley balloon catheter. In group I, thrombin
infusion caused an increase in pulmonary lymph flow (Qlym) with a gradual
increase in the lymph-to-plasma protein concentration ratio (L/P). In
complement-depleted sheep, thrombin caused a transient increase in Qlym,
which was associated with a decrease in L/P. In group I an increase in Pla
further increased Qlym but without a change in L/P, indicating an increase
in lung vascular permeability to proteins; whereas in the
decomplemented-thrombin sheep raising Pla increased Qlym but decreased L/P.
Results in the latter group were similar to those obtained in normal
animals after left atrial hypertension (group III). Therefore the
complement system participates in the increase in lung vascular
permeability following thrombin-induced microembolization.
