title: Meniscal transection rather than excision increases pain behavior and structural damage in experimental osteoarthritis in mice.
abstract: OBJECTIVE
  To evaluate pain behavior and structural damage in mice subjected to either meniscal transection or removal.
  
  
  METHODS
  Mice (10/group) were subjected to transection of the medial collateral and anterior cruciate ligaments (ACLT/MCLT) followed by either transection (meniscotomy) or removal (meniscectomy) of the medial meniscus. A control group was subjected only to transection of the ligaments. Pain was assessed using the electronic pressure-meter paw test. Cell influx, measured in joint exudates, and joint histopathology were assessed after 49 days. Four other groups subjected to meniscotomy received indomethacin, the inducible nitric oxide synthase (iNOS) inhibitor 1400W, morphine or the vehicles.
  
  
  RESULTS
  Both meniscotomy and meniscectomy groups displayed persistent and significant increase in pain behavior as compared to controls, being significantly more severe in the former. Cell influx was more intense in the meniscotomy as compared to the meniscectomy group. Structural damage at the tibia, but not at the femur, was also more severe in the meniscotomy group. Indomethacin and 1400W partially but significantly reduced pain whereas morphine abrogated pain behavior in meniscotomized mice.
  
  
  CONCLUSIONS
  Meniscal transection rather than resection promotes more severe pain and structural damage in mice. Administration of opioids, cyclooxygenase and nitric oxide (NO) synthase inhibitors provide analgesia in this model. Careful description of the structures damaged is crucial when reporting experimental osteoarthritis (OA).
authors.affiliation: Department of Public Health, Universidade da Integração Internacional da Lusofonia Afro-Brasileira, Redenção, Ceará, Brazil. Electronic address: acarolmelo@yahoo.com.br.
authors.forename: A C R
authors.initials: AC
authors.lastname: de Melo Leite
authors.affiliation: Department of Internal Medicine, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil. Electronic address: alinelioufc@hotmail.com.
authors.forename: M A A
authors.initials: MA
authors.lastname: Teotonio
authors.affiliation: Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil. Electronic address: virginiaccg@gmail.com.
authors.forename: V C C
authors.initials: VC
authors.lastname: Girão
authors.affiliation: Department of Pathology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil. Electronic address: mpompeu@ufc.br.
authors.forename: M M
authors.initials: MM
authors.lastname: de Lima Pompeu
authors.affiliation: Department of Internal Medicine, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil. Electronic address: rodolfo_k6@yahoo.com.br.
authors.forename: R
authors.initials: R
authors.lastname: de Melo Nunes
authors.affiliation: Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil. Electronic address: thicunha@usp.br.
authors.forename: T M
authors.initials: TM
authors.lastname: Cunha
authors.affiliation: Department of Internal Medicine, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil. Electronic address: caroldinelly@hotmail.com.
authors.forename: A C M D
authors.initials: AC
authors.lastname: Pinto
authors.affiliation: Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil. Electronic address: fdqcunha@fmrp.usp.br.
authors.forename: F
authors.initials: F
authors.lastname: de Queiroz Cunha
authors.affiliation: Department of Internal Medicine, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil. Electronic address: arocha@ufc.br.
authors.forename: F A C
authors.initials: FA
authors.lastname: Rocha
mesh_terms: D000818:Animals; D018771:Arthralgia / Q000209:etiology / Q000601:surgery*; D002358:Cartilage, Articular / Q000473:pathology* / Q000601:surgery; D004195:Disease Models, Animal; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology* / Q000601:surgery; D051379:Mice; D019637:Orthopedic Procedures / Q000379:methods*; D020370:Osteoarthritis, Knee / Q000150:complications / Q000473:pathology / Q000601:surgery*; D010147:Pain Measurement
keywords: Knee; Meniscus; Mice; Osteoarthritis; Pain