Comparison of Heat Shock Protein 70 Expression in Response to Different Non-Ablative Lasers: An In Vitro Study

The objective of our in vitro study was to compare the extent and timing of heat shock protein 70 (HSP70) expression following non-ablative fractional laser (NAFL) Er:Glass as well as Nd:YAG and alexandrite laser systems. The role of HSP70 has been established in wound healing. Reports indicate that HSP70 expression increases after skin laser interventions. Human skin ex vivo explants were subjected to different fluences and pulse durations by using the three laser systems. Assessments were conducted on days 0, 1, 3, and 5 post-laser intervention. HSP70 expression was assessed by immunohistochemistry using anti-HSP70. Er:Glass interventions caused the most significant increase in HSP70 expression whereas alexandrite interventions resulted in the least HSP70 expression, although significant compared with controls. HSP70 expression rose rapidly and dissipated quickly after Er:Glass and Nd:YAG interventions. Epidermal damage was most noted after Er:Glass interventions followed by the Nd:YAG and alexandrite systems. Non-ablative laser systems induce the expression of HSP70. Therefore, laser treatment may be considered 1-3 days before anticipated skin trauma to minimize scar formation provided the future validation of our data in an in vivo setting. The NAFL Er:Glass has the most potential for HSP70, yet it has also the most potential for complications.