title: Laser-induced thermal stress and the heat shock response in neural cells.
abstract: BACKGROUND
  The Ho: YAG laser is used extensively in orthopedic surgery. It offers a minimally invasive method of ablating tissue with precision. Previous studies have explored the effects of laser use on temperature during experimental foraminoplasty. To date, there has been limited work on the effects of thermal stress on cells in this context. Material and methods Cells were exposed either to heated medium or the Ho: YAG laser in the high-power mode. Heated medium was used as a stressor by (I) exposing groups of cells to a constant temperature of 45 degrees C for varying lengths of time: 5, 10, 15 and 20 min, and (II) exposing cells for a fixed length of time (5 min) to varying temperatures: 45 degrees C, 55 degrees C, 65 degrees C with a control treated at 37 degrees C. A third group was subjected to direct laser treatment. The effects of the treatments were assessed using trypan blue staining as a measure of viability and immunocytochemistry was used to measure changes in heat shock protein (HSP) expression.
  
  
  RESULTS
  There was a negative correlation between cell viability and HSP expression, and between cell viability and the severity of the treatment.
  
  
  CONCLUSIONS
  Our findings suggest a possible role for the Ho: YAG laser in spinal foraminoplasty based on the high level of cell viability in the treatment regimen that most closely mirrored the clinical application of the laser.
authors.affiliation: Imperial College, Faculty of Medicine, London.
authors.forename: Osa
authors.initials: O
authors.lastname: Emohare
authors.forename: Moustafa I
authors.initials: MI
authors.lastname: Hafez
authors.forename: Ann
authors.initials: A
authors.lastname: Sandison
authors.forename: Richard R H
authors.initials: RR
authors.lastname: Coombs
authors.forename: Ian D
authors.initials: ID
authors.lastname: McCarthy
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000502:physiology; D017586:Diskectomy / Q000379:methods; D005347:Fibroblasts / Q000502:physiology; D006360:Heat-Shock Proteins / Q000032:analysis*; D006358:Hot Temperature / Q000009:adverse effects*; D053685:Laser Therapy / Q000009:adverse effects*; D051381:Rats; D017208:Rats, Wistar; D012583:Schwann Cells / Q000502:physiology*; D046509:Tissue Culture Techniques
chemical_list: D006360:Heat-Shock Proteins