The effect of cobalt chloride on skin flap survival.

The effects of cobalt chloride on ischaemia-reperfusion injury were evaluated in skin flaps. Groin neurovascular island flaps, 3 x 6 cm, were elevated in rats and subjected to primary and secondary ischaemia. Primary ischaemia was produced by 1 hour occlusion of the femoral artery and vein and, 22 hours later, secondary ischaemia was produced by 3 hours venous occlusion. The treatment group received intraperitoneal cobalt chloride (5 or 10 mg/kg) at the time of secondary ischaemia. Flap survival was 80% in the control, 10 to 20% in the cobalt chloride treated, and 20% in the cobalt plus mannitol group. Mannitol (100 mg/kg) failed to prevent the harmful effects of cobalt. Skin flaps exposed to cobalt chloride exhibited increased thiobarbituric acid reactant (TBAR) levels of 20 to 30 times normal. Of the antioxidant enzymes, glutathione peroxidase activity increased by 40% (P < 0.01), whereas glutathione reductase activity decreased by 40% (P < 0.01) in the cobalt exposed groups. Glucose 6-phosphate dehydrogenase activity was not affected.