EFFECT OF METHYLPREDNISOLONE ON EDEMA FORMATION AFTER A MAJOR BURN

The mechanism of oedema formation distant from a burn site is only partially explained by an increase in capillary permeability. It has been demonstrated in quantitative terms that after a major burn, there is a large number of white blood cells (WBCs) stuck to the walls of venules in the distant microcirculation. Theoretical calculations predict a corresponding increase in post-capillary resistance, suggesting that WBC-sticking is partly responsible for oedema formation. In an attempt to discover whether the theoretical calculations persisted in vivo, the number of sticking WBCs in the mesenteric microvasculature of rats was determined at various times up to 48 h after a full-thickness scald burn to the back. The quantitative oedema formed was assessed by the wet weight/dry weight technique in burned skin, unburned skin, skeletal muscle and lung tissue. Half of the rats received methylprednisolone sodium succinate prior to burning to determine its effect on WBC-sticking and oedema formation. Conclusions from the experiment showed that a 30 per cent body surface, full-thickness burn results in significant increase in WBC-sticking in mesenteric microcirculation in animals. Pretreatment with systemic methylprednisolone sodium succinate decreased the magnitude of this change. Pretreatment with methylprednisolone was not effective in reducing oedema formation to statistically significant levels, although pretreated animals consistently showed less oedema formation than those which were untreated. Correlation between the number of adherent WBCs in the mesenteric microvasculature and the quantity of oedema formed could not be demonstrated in this model. © 1979 John Wright & Sons Ltd.