title: Quantitative changes in collagen levels following 830-nm diode laser welding.
abstract: OBJECTIVE
  The actual mechanism by which laser irradiation welds tissue is presently unknown; however, collagen is a major constituent of tissue welded by laser irradiation.
  
  
  METHODS
  Collagen was extracted from the abdominal aorta of Wistar rats by acetic acid extraction and repeated pepsin digestion after tissue welding (254 W/cm2) by using an 830-nm diode laser. The collagen levels were determined by using the Sircol Collagen Assay (Biocolor, Northern Ireland).
  
  
  RESULTS
  Compared with untreated aorta, the collagen content of the treated vessel was obvious decreased (P < 0.001) immediately after laser irradiation. Levels then increased by day 3, with a peak at day 10 (P < 0.002). The collagen content returned to normal levels on day 30 and remained at this level throughout the rest of the experimental period.
  
  
  CONCLUSIONS
  These results suggest that a proportion of the collagen molecules in the vessel are denatured by the heat of the laser. Collagen synthesis is stimulated during the healing process after laser welding with the parameters used in the present study.
authors.affiliation: Montpellier I University, Laboratory of Experimental Anatomy, Faculty of Medicine, Nimes, France.
authors.forename: J
authors.initials: J
authors.lastname: Tang
authors.forename: D
authors.initials: D
authors.lastname: O'Callaghan
authors.forename: S
authors.initials: S
authors.lastname: Rouy
authors.forename: G
authors.initials: G
authors.lastname: Godlewski
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000818:Animals; D001012:Aorta, Abdominal / Q000737:chemistry / Q000601:surgery; D003094:Collagen / Q000032:analysis* / Q000096:biosynthesis; D005500:Follow-Up Studies; D006358:Hot Temperature; D017075:Laser Coagulation; D010434:Pepsin A / Q000737:chemistry; D011489:Protein Denaturation; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012997:Solvents / Q000737:chemistry
chemical_list: D012997:Solvents; D003094:Collagen; D010434:Pepsin A; D019342:Acetic Acid