Burn depth affects dermal interstitial fluid pressure, free radical production, and serum histamine levels in rats

We measured the amount of edema and the free radical production in burn-injured skin and the serum histamine levels, as well as changes in dermal interstitial fluid pressure.

Thirty-six Wistar rats with 20% total body surface area burns of different depth were resuscitated by lactated Ringer's solution intravenously. The rats were divided into a deep burn (DB) group (n = 12), a superficial dermal burn (SDB) group (n = 12), and a sham burn (Sham) group (n = 12). Dermal interstitial fluid hydrostatic pressure (Pif), total skin water and xanthine oxidase activity, and serum histamine levels were measured until 60 minutes postburn.

In the DB group, dermal Pif significantly fell to -35.9 +/- 11.0 and -40.9 +/- 7.0 mm Hg at 10 and 15 minutes postburn, respectively (p < 0.05); it returned to preburn values at 50 minutes postburn. In the SDB group, dermal Pif was slightly negative but did not markedly change. Total skin water was significantly higher than that of the DB and the Sham groups; however, in the SDB group, serum histamine and dermal xanthine oxidase were significantly higher than in the DB group at 15, 30, and 45 minutes postburn (p < 0.05).

The fluid-resuscitated DB produced a more negative dermal Pif than the SDB, but less dermal edema. In contrast, the SDB appeared to mainly generate dermal edema formation by wound free radical production and serum histamine release. The dermal Pif is one of the factors associated with edema formation immediately after deep burns. However, an increase in vascular permeability associated with oxygen radical production plays a more important role in dermal edema formation than does dermal Pif.