Esfandiari Adeleh, Loya Theresa, Lee Jeffrey L
Department of Otolaryngology, Charles R. Drew University of Medicine and Science, King/Drew Medical Center, Los Angeles, CA 90059, USA.
J Natl Med Assoc. 2002 Jun;94(6):506-10.
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.
在加利福尼亚州洛杉矶市查尔斯·R·德鲁大学动物饲养所进行的一项社会行为学研究中，我们在30只作为对照的长 Evans 大鼠中观察到25例皮肤肿瘤。研究开始时这些动物为10周龄。所有皮肤肿瘤均在18至26个月龄时出现，并在9个月的时间里缓慢增大。8只雄性和6只雌性出现了多个结节。没有肿瘤消退。肿瘤位于后腿周围和背内侧区域，大小为1至2厘米。体格检查发现边界清晰的坚实皮肤肿块。大多数肿瘤结节位于真皮内，有些有中央溃疡或充满角蛋白的核心。对部分肿瘤进行的显微镜检查显示为典型的角化棘皮瘤表现，而其他肿瘤则显示出提示鳞状细胞癌的组织学特征。这些发现表明老年长 Evans 大鼠的自发性皮肤肿瘤发生率很高（83%）。据我们所知，文献中尚未描述老年啮齿动物如此高的皮肤肿瘤发生率。此外，应进行进一步研究以证实这些发现，并评估这些啮齿动物是否可作为研究衰老过程中免疫系统变化的模型。
