Detection of free radicals in reperfused dog skin flaps using electron paramagnetic resonance spectroscopy: A pilot study

Abstract

This is a preliminary investigation of the usefulness of spin-trapping electron paramagnetic resonance (EPR) in detecting oxygen-derived free radicals after reperfusion of ischemic skin flaps. Fourteen island skin flaps approximately 12 cm long by 6 cm wide based on the caudal superficial epigastric vessels were isolated in seven dogs. Seven of the paired skin flaps were subjected to 4 hours of arterial and venous occlusion. The opposite skin flap on each dog served as a perfused control. Spin trapping-EPR was able to detect radical adducts in five of the seven reperfused skin flaps. Hyperfine splitting constants of the radical adducts from the blood of three of the flaps confirmed biologically derived free radical production. Contaminating EPR signals from free radicals created in the manufacture of plastics probably masked any biologically derived radical adducts in the remaining flaps. The authors conclude that EPR-spin trapping may be a valuable tool in the study of the importance of oxygen-derived free radicals in the failure of skin flaps subjected to transient ischemia.

Reperfusion injury and reactive oxygen species: The evolution of a concept

“…2 ). This approach, which has been applied to heart [100] , [101] , kidney [102] , skin [103] , retina [104] , lung [105] , intestine [106] , liver [107] , and monolayers of cultured cells [108] , [109] , has revealed that the enhanced ROS production elicited by I/R is detected immediately (within 20 s) following reperfusion and that superoxide ( ) is the parent radical that serves as a precursor for the hydroxyl radical, carbon-centered radicals and other secondary species [2] , [110] . The more recent application of proteomic and genomic mapping to tissues (or cells) exposed to I/R (or H/R) is providing novel insights into the responses of specific proteins and genes to the oxidative stress that accompanies this condition [111] , [112] , [113] , [114] .…”

An In Vivo Study of Free Radicals Generated in Murine Skin by Protoporphyrin IX and Visible Light

“…Miller et al . (11) have detected free radicals in the perfused dog skin flap using the nitrone spin trap α‐4‐pyridyl‐ N‐tert ‐butylnitrone (PBN). PBN has also been successfully used to detect free radicals in skin lipids from mice exposed to cumene hydroperoxide (10), whereas α‐(4‐pyridyl‐1‐oxide)‐ N‐tert ‐butylnitrone (POBN) trapped radicals in lung lipids from mice exposed to lipopolysaccharide (12).…”

Electron paramagnetic resonance as a unique tool for skin and hair research

“…Nevertheless, using the specially shaped surface‐coil‐type resonator (39), the real in vivo EPR experiment is possible, regardless of whether it was performed on normal or pathological skin. Nevertheless, specifically dermatological EPR studies have been performed on all levels of skin organization using skin specimens (40,41), perfused skin flaps (42), biopsies (43,44), homogenates (45,46) and skin cells cultured in vitro (47,48). Finally EPR studies on model liposomes (49) and biological membranes (50), although in fact expanding beyond the strictly understood field of interest, are often intuitively associated with dermatology and cosmetology.…”

“…In dermatology, EPR spectroscopy of free radicals as serving to estimate the general redox state in vivo (81) may be used to identify the mechanisms of their production (42–45,64) and utilization (46), to test effective, natural or artificial (79,82,83) antioxidants , to identify potential pro‐oxidants (76,84) and to explore them in therapy , e.g. photodynamic therapy of various skin diseases (85) including tumors (76).…”