title: Collagen fibers in the rectus abdominis muscle of cadavers of different age.
abstract: OBJECTIVE
  To assess collagen content and types in the rectus abdominis muscle of cadavers of different ages.
  
  
  METHODS
  Forty fresh adult male cadavers within 24 h of death were obtained from an Institute of Legal Medicine and divided by age at death into Group 1 (mean age, 23.3 years; range, 18-30 years; n = 20) and Group 2 (mean age, 46.2 years; range, 31-60 years; n = 20). From each cadaver, samples of the rectus abdominis muscle measuring 1 cm(2) were collected 3 cm superiorly and 2 cm inferiorly to the umbilicus. Histological sections were prepared and stained with picrosirius red and Masson's trichrome stain for visualization of total collagen fibers, and immunohistochemical analysis was performed to distinguish types I, II, III, IV and V collagen.
  
  
  RESULTS
  No significant differences in total collagen were found between groups by Masson's trichrome staining. However, picrosirius red staining revealed a significantly greater amount and higher concentration of total collagen and types I and III collagen in Group 1 than in Group 2 (P < 0.05). All but type II collagen were detected by immunohistochemistry in both groups. No significant difference in type IV collagen was found between groups. Type V collagen was detected by immunohistochemistry in both groups, but quantification was not possible due to background staining.
  
  
  CONCLUSIONS
  The amounts of types I and III collagen in the rectus abdominis muscle were significantly smaller in older subjects.
authors.affiliation: Division of Plastic Surgery, Universidade Federal de São Paulo (UNIFESP), Rua Napoleão de Barros 715, 4o. andar, São Paulo, SP, 04023-062, Brazil.
authors.forename: E N C
authors.initials: EN
authors.lastname: Calvi
authors.forename: F X
authors.initials: FX
authors.lastname: Nahas
authors.forename: M V
authors.initials: MV
authors.lastname: Barbosa
authors.forename: J A
authors.initials: JA
authors.lastname: Calil
authors.forename: S S M
authors.initials: SS
authors.lastname: Ihara
authors.forename: Y
authors.initials: Y
authors.lastname: Juliano
authors.forename: L M
authors.initials: LM
authors.lastname: Ferreira
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002102:Cadaver; D003094:Collagen / Q000032:analysis*; D024042:Collagen Type I / Q000032:analysis; D024061:Collagen Type III / Q000032:analysis; D003643:Death; D006801:Humans; D008297:Male; D008875:Middle Aged; D017568:Rectus Abdominis / Q000737:chemistry* / Q000473:pathology; D055815:Young Adult
chemical_list: D024042:Collagen Type I; D024061:Collagen Type III; D003094:Collagen