THE EFFECT OF PENTOXIFYLLINE ON ISCHEMIA AND REPERFUSION INJURY IN THE RAT CREMASTER MUSCLE

The accumulation of leukocytes is believed to contribute to reperfusio n injury following ischemia. The purpose of this study was to determin e if pentoxifylline (PTX) would ameliorate reperfusion injury by preve nting activation of leukocytes. Male Wistar rats received 40 mg/kg of PTX orally in water for 6 days, and a single dose of PTX (30 mg/kg) in traarterially before experiments. Control measurements of red-cell vel ocity and inside diameter were made in first-through-third-order arter ioles (1A-3A) of the cremaster muscle, along with the number of rollin g and sticking leukocytes (WBC) in venules and the density of Bowing c apillaries, by intravital microscopy. The muscles were then subjected to total ischemia for 2 hr by arterial clamping, followed by a repeat of the measurements during reperfusion. The number of both rolling and sticking WBCs was not different between the two groups during the con trol period but, following reperfusion, there were significantly fewer WBCs rolling and sticking in the venules of the PTX group at the meas ured times (immediately, 1, 2, and 3 hr after reperfusion). Arteriolar blood now was lower than initial values during the first hour of repe rfusion in both groups. But while blood flow decreased further in the untreated group, it significantly improved in the PTX group. There wer e no significant differences in arteriolar diameter or density of flow ing capillaries between the two groups at any time. Treatment with PTX prevented accumulation of rolling and sticking leukocytes following r eperfusion. This may contribute to the improved arteriolar blood flow following 2 hr of ischemia.