Abstract
We report 25 cases of skin neoplasm observed among 30 Long Evans rats serving as controls in a psychosocial behavioral study conducted in the Vivarium at Charles R. Drew University, Los Angeles, CA. The animals were 10 weeks old at the beginning of the study. All the skin tumors developed at 18 to 26 months of age and slowly enlarged over a period of 9 months. Multiple nodules occurred in 8 males and 6 females. None of the tumors regressed. The tumors were located around the hind leg and dorso-medial area and measured 1 to 2 cm. Physical examination revealed firm well demarcated dermal masses. Most of the tumor nodules were intradermal, and some had a central ulcerated or keratin-filled core. Microscopic examination performed on some of the tumors showed findings of classic Keratoacanthoma, whereas others showed histologic features suggestive of squamous cell carcinoma. These findings indicate a high rate (83%) of spontaneous skin neoplasms among aging Long Evans rats. To our knowledge, such a high rate of skin neoplasms in aged rodents has not been described in the literature. Furthermore, further studies should be undertaken to confirm these findings and to assess whether these rodents might serve as a model for studying the alterations in the immune system with aging.
Full text
PDF




Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Albright J. W., Albright J. F. Age-associated impairment of murine natural killer activity. Proc Natl Acad Sci U S A. 1983 Oct;80(20):6371–6375. doi: 10.1073/pnas.80.20.6371. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Davila D. R., Kelley K. W. Sex differences in lectin-induced interleukin-2 synthesis in aging rats. Mech Ageing Dev. 1988 Sep;44(3):231–240. doi: 10.1016/0047-6374(88)90024-3. [DOI] [PubMed] [Google Scholar]
- Foad B. S., Adams L. E., Yamauchi Y., Litwin A. Phytomitogen responses of peripheral blood lymphocytes in young and older subjects. Clin Exp Immunol. 1974 Aug;17(4):657–664. [PMC free article] [PubMed] [Google Scholar]
- Hefton J. M., Darlington G. J., Casazza B. A., Weksler M. E. Immunologic studies of aging. V. Impaired proliferation of PHA responsive human lymphocytes in culture. J Immunol. 1980 Sep;125(3):1007–1010. [PubMed] [Google Scholar]
- Hung C. Y., Perkins E. H., Yang W. K. Age-related refractoriness of PHA-induced lymphocyte transformation. II. 125-I-PHA binding to spleen cells from young and old mice. Mech Ageing Dev. 1975 Mar-Apr;4(2):103–112. doi: 10.1016/0047-6374(75)90012-3. [DOI] [PubMed] [Google Scholar]
- Kern W. H., McCray M. K. The histopathologic differentiation of keratoacanthoma and squamous cell carcinoma of the skin. J Cutan Pathol. 1980 Oct;7(5):318–325. doi: 10.1111/j.1600-0560.1980.tb01202.x. [DOI] [PubMed] [Google Scholar]
- Lesourd B. M., Meaume S. Cell mediated immunity changes in ageing, relative importance of cell subpopulation switches and of nutritional factors. Immunol Lett. 1994 Jun;40(3):235–242. doi: 10.1016/0165-2478(94)00062-x. [DOI] [PubMed] [Google Scholar]
- McGregor J. M., Farthing A., Crook T., Yu C. C., Dublin E. A., Levison D. A., MacDonald D. M. Posttransplant skin cancer: a possible role for p53 gene mutation but not for oncogenic human papillomaviruses. J Am Acad Dermatol. 1994 May;30(5 Pt 1):701–706. doi: 10.1016/s0190-9622(08)81498-3. [DOI] [PubMed] [Google Scholar]
- Miller R. A. The aging immune system: primer and prospectus. Science. 1996 Jul 5;273(5271):70–74. doi: 10.1126/science.273.5271.70. [DOI] [PubMed] [Google Scholar]
- Odio M., Brodish A., Ricardo M. J., Jr Effects on immune responses by chronic stress are modulated by aging. Brain Behav Immun. 1987 Sep;1(3):204–215. doi: 10.1016/0889-1591(87)90023-7. [DOI] [PubMed] [Google Scholar]
- Rook A., Whimster I. Keratoacanthoma--a thirty year retrospect. Br J Dermatol. 1979 Jan;100(1):41–47. doi: 10.1111/j.1365-2133.1979.tb03568.x. [DOI] [PubMed] [Google Scholar]
- Sommer M. M. Spontaneous skin neoplasms in Long-Evans rats. Toxicol Pathol. 1997 Sep-Oct;25(5):506–510. doi: 10.1177/019262339702500513. [DOI] [PubMed] [Google Scholar]
- Sullivan J. J., Colditz G. A. Keratoacanthoma in a sub-tropical climate. Australas J Dermatol. 1979 Apr;20(1):34–40. doi: 10.1111/j.1440-0960.1979.tb00122.x. [DOI] [PubMed] [Google Scholar]
- Weindruch R., Devens B. H., Raff H. V., Walford R. L. Influence of dietary restriction and aging on natural killer cell activity in mice. J Immunol. 1983 Feb;130(2):993–996. [PubMed] [Google Scholar]
- Wu W. T., Pahlavani M., Cheung H. T., Richardson A. The effect of aging on the expression of interleukin 2 messenger ribonucleic acid. Cell Immunol. 1986 Jun;100(1):224–231. doi: 10.1016/0008-8749(86)90021-3. [DOI] [PubMed] [Google Scholar]
- Zwicker G. M., Eyster R. C., Sells D. M., Gass J. H. Spontaneous skin neoplasms in aged Sprague-Dawley rats. Toxicol Pathol. 1992;20(3 Pt 1):327–340. doi: 10.1177/019262339202000303. [DOI] [PubMed] [Google Scholar]



