title: Dependence of cytokine levels on the sex of experimental animals: a pilot study on the effect of oestrogen in the temporomandibular joint synovial tissues.
abstract: The aim of this study was to evaluate the effects of 17β-oestradiol (E2) on cartilage thickness and cytokine levels in the temporomandibular joint (TMJ). Thirty rats (15 female, 15 male) were orchidectomized (ORX), ovariectomized (OVX), or sham-operated. After 21 days, animals were assigned to six groups: (1) sham-ORX; (2) ORX; (3) ORX+E2; (4) sham-OVX; (5) OVX; and (6) OVX+E2. Treatments were administered daily for 21 days. The thickness of cartilage layers (fibrous, proliferative, maturation, and hypertrophic) and cytokine levels (interleukins IL-1α, IL-1β, IL-6, and tumour necrosis factor alpha (TNF-α)) were measured by histomorphometry and ELISA, respectively. Kruskal-Wallis/Dunn's tests were used (alpha=5%). Sham-ORX showed thicker layers than ORX+E2, but not thicker than ORX. All layers, except the hypertrophic layer, were thicker in sham-OVX than OVX or OVX+E2. Although IL-1β levels were higher in castrated animals, E2 did not affect the level of this cytokine. IL-1α levels were higher in both ORX (P=0.0010) and ORX+E2 (P=0.0053) than in sham-ORX. However, E2 decreased IL-1α levels in OVX (P=0.0129). When compared to sham-ORX/OVX, IL-6 levels were not affected by E2 in males but were reduced in OVX (P=0.0079) and increased in OVX+E2 (P=0.0434). Levels of TNF-α were reduced by E2 in both ORX+E2 and OVX+E2. E2 treatment caused gender- and layer-dependent changes in the cartilage. Castration increased all cytokine levels, except for IL-6, without respect to gender.
authors.affiliation: Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, São Paulo, Brazil. Electronic address: sfigueroba@uol.com.br.
authors.forename: S R
authors.initials: SR
authors.lastname: Figueroba
authors.affiliation: Department of General Biology, Area of Physiology, Pathophysiology, State University of Ponta Grossa, Ponta Grossa, Paraná, Brazil.
authors.forename: G C N
authors.initials: GC
authors.lastname: Franco
authors.affiliation: Department of Morphology, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, São Paulo, Brazil.
authors.forename: N F
authors.initials: NF
authors.lastname: Omar
authors.affiliation: Department of Morphology, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, São Paulo, Brazil.
authors.forename: M F
authors.initials: MF
authors.lastname: Groppo
authors.affiliation: Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, São Paulo, Brazil.
authors.forename: F C
authors.initials: FC
authors.lastname: Groppo
mesh_terms: D000818:Animals; D001835:Body Weight; D002358:Cartilage, Articular / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D008297:Male; D009919:Orchiectomy; D010052:Ovariectomy; D010865:Pilot Projects; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013583:Synovial Membrane / Q000378:metabolism*; D013704:Temporomandibular Joint / Q000378:metabolism*
chemical_list: D016207:Cytokines; D004958:Estradiol
keywords: cartilage; cytokine; gonadectomy; oestrogen; temporomandibular joint; testosterone