Effect of intravascular pneumococcal challenge on vascular permeability in rabbits

Tissue counts in lung, liver, and spleen were not significantly increased in PNC-challenged animals compared to saline-injected controls. In fact, tissue counts from PNC-challenged animals were significantly decreased in heart, kidney, and brain compared to saline-injected controls (P less than 0.05 by Mann-Whitney U test). Tissue radioactivity reflecting intravascular volume can be altered by changes in either tissue perfusion or vascular permeability. PNC sepsis is associated with both cardiovascular dysfunction [1] as well as complement activation with generation of cleavage products known to exert anaphylatoxin activity [2]. We could not demonstrate increased vascular permeability at 3 hr in the lungs or in any of the other five tissues studied. However, it is possible that some degree of increased vascular permeability could be obscured by concomitant tissue hypoperfusion.