title: FasL expression in articular discs of human temporomandibular joint and association with osteoarthrosis.
abstract: BACKGROUND
  Apoptosis is a programme of cell death which does not induce an inflammatory response. Recent previous research has suggested a correlation between temporomandibular internal derangement and apoptosis. Fas ligand (FasL) is an apoptosis-inducing factor, known to trigger apoptosis through distinct signal pathways. This study aims to examine, by immunohistochemistry, the expression of FasL in temporomandibular joint (TMJ) articular discs of patients with anterior disc displacement with reduction (ADDwR) and without reduction (ADDwoR) in patients with and without osteoarthrosis (OA).
  
  
  METHODS
  Forty-two (n = 42) TMJ articular discs were divided into two cut-offs: (i) 8 control, 17 ADDwR, 17 ADDwoR, and (ii) without OA (n = 25) and with OA (n = 17). The area of immunostaining was compared statistically between groups (P < 0.05).
  
  
  RESULTS
  Statistically significant differences were found in the expression of FasL in TMJ discs between the three groups (P = 0.001). ADDwR presented significant higher FasL expression when compared with ADDwoR (P < 0.001). Significant higher FasL expression was observed in the group without OA (P = 0.001). All patients without OA presented ADDwR, while all the patients with OA presented ADDwoR.
  
  
  CONCLUSIONS
  A higher area of in situ immunostaining of FasL was found in temporomandibular discs with reduction, which is the less severe condition. Moreover, a reduced expression of FasL in the discs of patients with osteoarthrosis was found, suggesting that some aspects of apoptosis might underlie the progression of TMJ disorders.
authors.affiliation: School of Health and Biosciences, Pontifícia Universidade Católica do Paraná (PUCPR), Curitiba, Brazil.
authors.forename: Flavio de Alcântara
authors.initials: Fde A
authors.lastname: Camejo
authors.forename: Luis Eduardo
authors.initials: LE
authors.lastname: Almeida
authors.forename: Andrea Duarte
authors.initials: AD
authors.lastname: Doetzer
authors.forename: Karina São Thiago
authors.initials: KS
authors.lastname: Caporal
authors.forename: Viviane
authors.initials: V
authors.lastname: Ambros
authors.forename: Marina
authors.initials: M
authors.lastname: Azevedo
authors.forename: Luciana Reis Azevedo
authors.initials: LR
authors.lastname: Alanis
authors.forename: Marcia
authors.initials: M
authors.lastname: Olandoski
authors.forename: Lucia
authors.initials: L
authors.lastname: Noronha
authors.forename: Paula Cristina
authors.initials: PC
authors.lastname: Trevilatto
mesh_terms: D000293:Adolescent; D000328:Adult; D017209:Apoptosis / Q000502:physiology; D002358:Cartilage, Articular / Q000737:chemistry* / Q000473:pathology / Q000601:surgery; D002462:Cell Membrane / Q000473:pathology; D019902:Chondrocytes / Q000473:pathology; D004396:Coloring Agents; D018450:Disease Progression; D053222:Fas Ligand Protein / Q000032:analysis*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007150:Immunohistochemistry; D004204:Joint Dislocations / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D013704:Temporomandibular Joint / Q000473:pathology*; D019224:Temporomandibular Joint Disc / Q000737:chemistry* / Q000473:pathology* / Q000601:surgery; D013705:Temporomandibular Joint Disorders / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D055815:Young Adult
chemical_list: D004396:Coloring Agents; C505661:FASLG protein, human; D053222:Fas Ligand Protein
keywords: apoptosis; disc derangement; osteoarthrosis; temporomandibular disorder