Spontaneous dwarf rat: A novel model for aging research

Kazunao Kuramoto, Shoichi Tahara, Toru Sasaki, Shigenobu Matsumoto, Takao Kaneko, Hiroshi Kondo, Makoto Yanabe, Shohei Takagi, Tadashi Shinkai

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Aim: Dwarf animal models can provide new models for aging research. For the spontaneous dwarf rat (SDR), a dwarf strain derived from the Sprague-Dawley (SD) rat, no data relevant to aging research are available. The present study aimed to examine its growth, hormonal background, lifespan and age-related diseases. Methods: Male SDR and SD rats were used for growth comparison and for immunohistochemistry and plasma hormonal analysis. SDR of each sex were maintained until natural death and then inspected pathologically. Results: SDR showed an apparent dwarfism in their youth. Immunohistochemistry indicated that the development of growth hormone (GH)-positive cells in the pituitary was insufficient in SDR. In SDR, plasma GH levels were lower than in SD rats. Moreover, both insulin-like growth factor-1 (IGF-1) and insulin levels were decreased compared to levels in SD rats. Male and female SDR showed a mean lifespan of 29.3 ± 3.3 and 26.8 ± 5.3 months, respectively. The main neoplastic lesions in SDR were pituitary and mammary tumors. Major non-neoplastic lesions were incisor malocclusion, heart disease, chronic nephropathy (male) and cerebral hemorrhage (female). Most cases of chronic nephropathy were mild. Conclusion: Compared with longevity data and pathological data reported for SD rats, the lifespan in SDR was increased by 20-40% in males and 10-20% in females, and SDR had characteristic decreases in pituitary and mammary tumors as well as in severe chronic nephropathy. The SDR, differing in endocrinology, longevity and pathology from the SD rat, is potentially a new animal model for aging research.

Original languageEnglish
Pages (from-to)94-101
Number of pages8
JournalGeriatrics and Gerontology International
Issue number1
Publication statusPublished - 2010 Jan
Externally publishedYes


  • Age-related diseases
  • Aging
  • Dwarf rat
  • Growth hormone
  • Insulin-like growth factor-1
  • Oxidative stress

ASJC Scopus subject areas

  • Health(social science)
  • Gerontology
  • Geriatrics and Gerontology


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