LIPID-PEROXIDATION IN FREE SKIN-GRAFTS IN RATS

Objective-To evaluate accumulation of products of lipid peroxidation i n free skin grafts in rats over 10 days after grafting. Design-Prospec tive analysis. Animals-30 adult Sprague-Dawley rats. Procedure-Free sk in grafts were applied to 1 hemithorax of 30 rats (2 groups, n = 15/ g roup), the other hemithorax acting as a nongrafted control. Biopsy spe cimens were taken from the nongrafted side of ail rats immediately bef ore and from the nongrafted and grafted sides immediately after the pr ocedure. Biopsy specimens of both sides of the thorax were performed o n days 1, 3, and 7 after grafting in group-1 rats, and on days 2, 4, a nd 10 after grafting in group-2 rats. Thiobarbituric acid (TBA) analys is for malondialdehyde and other aldehydic products (TEA-reactive subs tances) was used to determine lipid peroxidation. Concentration of TEA -reactive substances was determined by absorbance spectrophotometry at a wavelength of 532 nm. Results-Accumulation of products of lipid per oxidation, reflected by increase in absorbance, continued to increase over the 10 days of this study. Difference in absorption between the n ongraft and graft biopsy specimens was significant (P = 0.0011). Absor bance on days 3 and 4 was significantly higher than control and day-0 values (P less than or equal to 0.05). Absorbance on days 7 and 10 was significantly higher than control, day-0, and day-1 values (P less th an or equal to 0.05). Rate of increase in absorption was maximai at da y 4 and rapidly decreased thereafter. Conclusion-Accumulation of lipid peroxidation products in skin grafts may be best explained by oxygen- derived free radical-induced injury attributable to postischemic reper fusion. Maximal rate of accumulation corresponded to the known time of graft recirculation and revascularization. Clinical Relevance-Predict ability of free radical damage may allow timely pharmacologic interven tion to reduce radical formation and ameliorate effects of peroxidatio n. Such intervention may help increase free graft survival or mitigate the effects of vascular compromise to axial pattern flaps.