THE EFFECT OF MANNITOL AND ANISODAMIN ON THE PREVENTION OF FREE-RADICAL INJURY TO POSTISCHEMIA FLAPS - AN EXPERIMENTAL-STUDY

Rat abdominal skin flaps were subjected to total venous occlusion for 8 h. Five minutes before release of the vascular occlusion, mannitol, mannitol plus anisodamin, anisodamin or placebo (0.9% normal saline) w as administered intravenously. Drug treated flaps showed a statistical ly significant increase in the proportion of area surviving (P < 0.001 ). The combination of mannitol and anisodamin was not more effective t han either agent alone in increasing the proportion of area surviving. The results of biochemical analyses indicated that neither mannitol n or anisodamin affected xanthine oxidase activity (p > 0.05) but that b oth agents significantly reduced the increase of malondialdehyde (MDA) concentration caused by ischaemia-reperfusion (p < 0.01). Treatment w ith mannitol or anisodamin also prevented the increase of lactate and water content and the decrease in glucose content in the island skin f lap tissue which occurred on reperfusion. The data indicate that manni tol and/or anisodamin have the potential to salvage anticipated flap n ecrosis. It is possible that the mechanism of action is inhibition of damage caused by toxic oxygen species and improvement in capillary rep erfusion.