Objective: To evaluate accumulation of products of lipid peroxidation in free skin grafts in rats over 10 days after grafting.
Design: Prospective analysis.
Animals: 30 adult Sprague-Dawley rats.
Procedure: Free skin grafts were applied to 1 hemithorax of 30 rats (2 groups, n = 15/ group), the other hemithorax acting as a nongrafted control. Biopsy specimens were taken from the nongrafted side of all rats immediately before and from the nongrafted and grafted sides immediately after the procedure. Biopsy specimens of both sides of the thorax were performed on days 1, 3, and 7 after grafting in group-1 rats, and on days 2, 4, and 10 after grafting in group-2 rats. Thiobarbituric acid (TBA) analysis for malondialdehyde and other aldehydic products (TBA-reactive substances) was used to determine lipid peroxidation. Concentration of TBA-reactive substances was determined by absorbance spectrophotometry at a wavelength of 532 nm.
Results: Accumulation of products of lipid peroxidation, reflected by increase in absorbance, continued to increase over the 10 days of this study. Difference in absorption between the nongraft and graft biopsy specimens was significant (P = 0.0011). Absorbance on days 3 and 4 was significantly higher than control and day-0 values (P < or = 0.05). Absorbance on days 7 and 10 was significantly higher than control, day-0, and day-1 values (P < or = 0.05). Rate of increase in absorption was maximal at day 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 reperfusion. Maximal rate of accumulation corresponded to the known time of graft recirculation and revascularization.
Clinical relevance: Predictability of free radical damage may allow timely pharmacologic intervention to reduce radical formation and ameliorate effects of peroxidation. Such intervention may help increase free graft survival or mitigate the effects of vascular compromise to axial pattern flaps.