title: Differential age-related bone architecture changes between female and male STR/Ort mice.
abstract: The incidence of spontaneous osteoarthritis (OA) in female STR/Ort mice is much lower than that observed in male STR/Ort mice; however, the reason for the differential incidence of OA between sexes has not been elucidated. Here, we investigated and compared age- and sex-related bone mineral density and architectural changes in male and female STR/Ort mice. Bone architecture and bone mineral density (BMD) of femurs were examined in 5-, 10-, 15-, 20-, and 35-week-old male and female STR/Ort mice by microscopic computed tomography (µCT). Angular degrees of internal tibial torsion (ADITT) were also measured in mice at 5, 15, and 35 weeks of age. Earlier decreases of cancellous volume and BMD were found in male STR/Ort mice. Using µCT, an age-related decline of bone marrow space in femoral diaphysis was observed in both males and females but was more dramatic in females. In addition, an earlier increase of ADITT was observed in male STR/Ort mice, suggesting that internal rotation of the tibia may contribute to OA. Age- and sex-related bone architectural changes clearly differ between male and female STR/Ort mice. These differences in bone structure, particularly ADITT, may explain the differential incidence of OA in STR/Ort mice.
authors.affiliation: Department of Orthopedic Surgery, Kitasato University School of Medicine, Kanagawa, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Uchida
authors.forename: Ken
authors.initials: K
authors.lastname: Urabe
authors.forename: Kouji
authors.initials: K
authors.lastname: Naruse
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kozai
authors.forename: Kenji
authors.initials: K
authors.lastname: Onuma
authors.forename: Yuko
authors.initials: Y
authors.lastname: Mikuni-Takagaki
authors.forename: Isamu
authors.initials: I
authors.lastname: Kashima
authors.forename: Masaki
authors.initials: M
authors.lastname: Ueno
authors.forename: Rina
authors.initials: R
authors.lastname: Sakai
authors.forename: Moritoshi
authors.initials: M
authors.lastname: Itoman
authors.forename: Masashi
authors.initials: M
authors.lastname: Takaso
mesh_terms: D000367:Age Factors; D000818:Animals; D001169:Arthritis, Experimental / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology*; D015519:Bone Density; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000166:cytology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology*; D010052:Ovariectomy / Q000009:adverse effects*; D011859:Radiography; D012737:Sex Factors; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology; D014055:Tomography, Emission-Computed; D014102:Torsion Abnormality / Q000473:pathology