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Home / Journal of the American Association for Laboratory Animal Science, Volume 41, Number 5

Open Access Review of Growth Plate Closure Compared with Age at Sexual Maturity and Lifespan in Laboratory Animals

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Although it is assumed that most mammals experience growth plate closure and cessation of bone growth soon after sexual maturity, bone growth in rats continues throughout their lifespan. The rat was compared to other laboratory animals to assess differences in the duration of bone growth and its relationship to age at sexual maturity and lifespan. We reviewed the literature from 1966 to March 1999 by searching MEDLINE and other databases. Growth closure times and age at sexual maturity were retrieved for the mouse, rabbit, dog, cat, sheep, cow, horse, nonhuman primates, and human. For all species, we calculated the ratios of: 1) age at growth plate closure to lifespan, 2) age at growth plate closure to age at sexual maturity, and 3) age at sexual maturity to average lifespan. The ratio of age at physis closure to the average lifespan was large for the rat (22 to 35) and showed some overlap with that of humans (17 to 25); this ratio was comparatively small in all other nonhuman species (range, 4 to 17). This finding indicates that bone growth continues in the rat for a greater proportion of their lifespan than does that in other species. The ratio of age at physis closure to age at sexual maturity was larger for the rat (5 to 6) than that for other species, indicating that bone growth continues much longer after sexual maturity in rats than in other animals. The ratio of age at sexual maturity to average lifespan was largest for humans and nonhuman primates (13 to 14), indicating the increased time to reach puberty versus that in other species. These differences are important for studies in which animal models are used in research involving bone growth.

Document Type: Research Article

Affiliations: 1: Animal Care and Veterinary Service, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5 2: Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5 3: Division of Orthopaedic Surgery, Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada K1H 8L6

Publication date: September 1, 2002

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  • The Journal of the American Association for Laboratory Animal Science (JAALAS) serves as an official communication vehicle for the American Association for Laboratory Animal Science (AALAS). The journal includes a section of refereed articles and a section of AALAS association news. The mission of the refereed section of the journal is to disseminate high-quality, peer-reviewed information on animal biology, technology, facility operations, management, and compliance as relevant to the AALAS membership. JAALAS accepts research reports (data-based) or scholarly reports (literature-based), with the caveat that all articles, including solicited manuscripts, must include appropriate references and must undergo peer review.

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