Prostaglandin release and altered microvascular integrity after burn injury

Abstract

Alterations in microvascular integrity occur after thermal injury in both burned and nonburned tissues including the lung resulting in increases in transvascular fluid and protein flux. Our purpose was to determine the role of the potent vasoactive prostaglandins, prostacyclin (PGI 2) and thromboxane (TxA 2), in this process. We monitored fluid flux and protein permeability in lung, and in burned (B) and nonburned (NB) soft tissue using lymph flow, Q ̇ L , and lymph protein content in 14 adult sheep after a 30% body burn. We measured levels of TxA 2 as TxB 2 and PGI 2 as 6-keto-PGF 1α in lymph and plasma over a 48-hr period. Q ̇ L increased by 200–300% in lung and NB tissue in the first 12 hr, returning to baseline by 48 hr. Protein permeability was unchanged in lung and transiently increased in NB. Lymph PGI 2 was increased, from 0.3 to 1.5 ng/ml in lung and 0.5 to 1.7 ng/ml in NB. Levels returned to baseline with Q ̇ L . TxB 2 levels were not increased. In B tissue, Q ̇ L increased by 5- to 10-fold as did protein permeability, with PGI 2 levels increasing from 0.3 to 10.9 ng/ml. Both Q ̇ L and PGI 2 remained increased for over 48 hr. TxB 2 was unchanged. We, therefore, found that variable degrees of microvascular change occurred in lung, NB, and B soft tissue after thermal injury. Lymph PGI 2 corresponded in both degree and time course with the measured microvascular injury. Thromboxane did not appear to play a role in this process.