Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay to characterize histopathologic changes following thermal injury

Background: Despite the wide application of lasers and radiofrequency (RF) surgery in dermatology, it is difficult to find studies showing the extent of damage dependent on cell death. Objective: We evaluated histopathologic changes following in vivo thermal damage generated by CO2 laser, 1,444 nm long-pulsed neodymium:yttrium-Aluminum-garnet (LP Nd:YAG) laser and RF emitting electrosurgical unit. Methods: Thermal damage was induced by the above instruments on ventral skin of rat. Specimens were stained with hematoxylin and eosin, along with a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay, to highlight the degree of irreversible cellular injury. Results: The volume of vaporization was largest with the CO2 laser. Area of cell death area identified by TUNEL assay, when arranged from widest to narrowest, was 1,444 nm LP Nd:YAG laser, CO2 laser, and RF emitting electrosurgical unit. Conclusion: This histopathologic evaluation of the acute characterization of injury across devices may be advantageous for attaining better treatment outcomes.