EICOSANOIDS AND INFLAMMATORY CELLS IN FROSTBITTEN TISSUE - PROSTACYCLIN, THROMBOXANE, POLYMORPHONUCLEAR LEUKOCYTES, AND MAST-CELLS

The pathophysiology of cold injury is still controversial. An inflamma tory process has been implicated as the underlying mechanism and certa in anti-inflammatory substances such as ibuprofen and acetylsalicylic acid have been used in the clinical treatment of frostbite injury. It has been postulated that the progressive ischemic necrosis is secondar y to excessive thromboxane A(2) production, which upsets the normal ba lance between prostacyclin (prostaglandin Ig) and thromboxane A(2). It was aimed to clarify the pathophysiology of cold injury in this study . Twenty-one New Zealand White rabbits, each weighing 1.2 to 2.9 kg, w ere divided into control (n = 10) and frost bitten (n = 11) groups the randomly. The rabbit ears in the frostbitten group were subjected to cold injury, and the levels of thromboxane A(2) (as thromboxane B-2) a nd of prostaglandin I-2 (as 6-keto-prostaglandin F-1 alpha) and the nu mber of inflammatory cells (polymorphonuclear leukocytes and mast cell s) were measured in normal and frostbitten skin of rabbit ears. The le vels of 6-keto prostaglandin F-1 alpha and thromboxane B-2, the stable metabolites of prostaglandin I-2 and thromboxane A(2), respectively, were increased in a statistically significant way (p < 0.002) by frost bite injury; however, thromboxane B-2 increased more than 6-keto prost aglandin F-1 alpha. Polymorphonuclear leukocytes and mast cells, absen t in normal skin, were present in the frostbitten skin. There was a st atistically significant (p < 0.01) correlation between the time a rabb it ear was maintained at below -10 degrees C and skin survival and bet ween the weights of rabbits and skin survival (p < 0.024). All these f indings suggest that inflammation is involved in frostbite injury; a d ecrease in prostaglandin I-2/thromboxane A(2) ratio could be one of th e factors leading to necrosis; the bigger the animal, the better its a bility to counter frostbite.