title: Pulse duration determines levels of Hsp70 induction in tissues following laser irradiation.
abstract: Induction of heat shock protein (Hsp) expression correlates with cytoprotection, reduced tissue damage, and accelerated healing in animal models. Since Hsps are transcriptionally activated in response to stress, they can act as stress indicators in burn injury or surgical procedures that produce heat and thermal change. A fast in vivo readout for induction of Hsp transcription in tissues would allow for the study of these proteins as therapeutic effect mediators and reporters of thermal stress∕damage. We used a transgenic reporter mouse in which a luciferase expression is controlled by the regulatory region of the inducible 70 kilodalton (kDa) Hsp as a rapid readout of cellular responses to laser-mediated thermal stress∕injury in mouse skin. We assessed the pulse duration dependence of the Hsp70 expression after irradiation with a CO(2) laser at 10.6 μm in wavelength over a range of 1000 to 1 ms. Hsp70 induction varied with changes in laser pulse durations and radiant exposures, which defined the ranges at which thermal activation of Hsp70 can be used to protect cells from subsequent stress, and reveals the window of thermal stress that tissues can endure.
authors.affiliation: Stanford University School of Medicine, Department of Pediatrics, Clark Center E-150, 318 Campus Drive, Stanford, California 94305-5427, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Mackanos
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Contag
mesh_terms: D000818:Animals; D005260:Female; D015870:Gene Expression; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D018869:Heat-Shock Response / Q000235:genetics / Q000502:physiology; D006358:Hot Temperature / Q000009:adverse effects / Q000627:therapeutic use; D054020:Lasers, Gas / Q000009:adverse effects* / Q000627:therapeutic use*; D049409:Luciferases, Firefly / Q000235:genetics; D008163:Luminescent Measurements; D051379:Mice; D008822:Mice, Transgenic; D013312:Stress, Physiological; D013997:Time Factors
chemical_list: D018840:HSP70 Heat-Shock Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D049409:Luciferases, Firefly