title: Loss of Ovarian Function Results in Increased Loss of Skeletal Muscle in Arthritic Rats.
abstract: OBJECTIVE
  We studied the effects of loss of ovarian function (ovariectomy) on muscle mass of gastrocnemius and the mRNA levels of IGF-1, atrogin-1, MuRF-1, and myostatin in an experimental model of rheumatoid arthritis in rats.
  
  
  METHODS
  We randomly allocated 24 female Wistar rats (9 weeks, 195.3 ± 17.4 grams) into four groups: control (CT-Sham; n = 6); rheumatoid arthritis (RA; n = 6); ovariectomy without rheumatoid arthritis (OV; n = 6); ovariectomy with rheumatoid arthritis (RAOV; n = 6). We performed the ovariectomy (OV and RAOV) or Sham (CT-Sham or RA) procedures at the same time, fifteen days before the rheumatoid arthritis induction. The RA and RAOV groups were immunized and then were injected with Met-BSA in the tibiotarsal joint. After 15 days of intra-articular injections the animals were euthanized. We evaluated the external manifestations of rheumatoid arthritis (perimeter joint) as well as animal weight, and food intake throughout the study. We also analyzed the cross-sectional areas (CSA) of gastrocnemius muscle fibers in 200 fibers (H&E method). In the gastrocnemius muscle, we analyzed mRNA expression by quantitative real time PCR followed by the Livak method (ΔΔCT).
  
  
  RESULTS
  The rheumatoid arthritis induced reduction in CSA of gastrocnemius muscle fibers. The RAOV group showed a lower CSA of gastrocnemius muscle fibers compared to RA and CT-Sham groups. Skeletal muscle IGF-1 mRNA increased in arthritics and ovariectomized rats. The increased IGF-1 mRNA was higher in OV groups than in the RA and RAOV groups. Antrogin-1 mRNA also increased in the gastrocnemius muscle of arthritic and ovariectomized rats. However, the increased atrogin-1 mRNA was higher in RAOV groups than in the RA and OV groups. Gastrocnemius muscle MuRF-1 mRNA increased in the OV and RAOV groups, but not in the RA and Sham groups. However, the RAOV group showed higher MuRF-1 mRNA than the OV group. The myostatin gene expression was similar in all groups.
  
  
  CONCLUSIONS
  Loss of ovarian function results in increased loss of skeletal muscle-related ubiquitin ligases atrogin-1 and MuRF-1 in arthritic rats.
authors.affiliation: Exercise Biology Research Group (BioEx), Health Sciences Institute, Universidade Federal do Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.
authors.forename: Roberto
authors.initials: R
authors.lastname: Furlanetto Júnior
authors.affiliation: Exercise Biology Research Group (BioEx), Health Sciences Institute, Universidade Federal do Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.
authors.forename: Fernanda Maria
authors.initials: FM
authors.lastname: Martins
authors.affiliation: Exercise Biology Research Group (BioEx), Health Sciences Institute, Universidade Federal do Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.
authors.forename: Anselmo Alves de
authors.initials: AA
authors.lastname: Oliveira
authors.affiliation: Exercise Biology Research Group (BioEx), Health Sciences Institute, Universidade Federal do Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.
authors.forename: Paulo Ricardo Prado
authors.initials: PR
authors.lastname: Nunes
authors.affiliation: Research Institute of Oncology (IPON), Discipline of Gynecology and Obstetrics, UFTM, Uberaba, Minas Gerais, Brazil.
authors.forename: Márcia Antoniazi
authors.initials: MA
authors.lastname: Michelin
authors.affiliation: Research Institute of Oncology (IPON), Discipline of Gynecology and Obstetrics, UFTM, Uberaba, Minas Gerais, Brazil.
authors.forename: Eddie Fernando Candido
authors.initials: EF
authors.lastname: Murta
authors.affiliation: Exercise Biology Research Group (BioEx), Health Sciences Institute, Universidade Federal do Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.
authors.forename: Fábio Lera
authors.initials: FL
authors.lastname: Orsatti
mesh_terms: D000818:Animals; D001172:Arthritis, Rheumatoid / Q000503:physiopathology*; D004195:Disease Models, Animal; D005260:Female; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000503:physiopathology*; D055435:Myostatin / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism; D000070584:Tripartite Motif Proteins / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: C525913:Mstn protein, rat; D009124:Muscle Proteins; D055435:Myostatin; D000070584:Tripartite Motif Proteins; D007334:Insulin-Like Growth Factor I; C486692:Fbxo32 protein, rat; D044843:SKP Cullin F-Box Protein Ligases; C499086:Trim63 protein, rat; D044767:Ubiquitin-Protein Ligases