Transplacental Carcinogenicity of N-Ethyl-N-Nitrosourea in Sprague-Dawley Rats

Abstract

N-Ethyl-N-nitrosourea (ENU) is known to induce a wide spectrum of tumors in various organs in adult experimental animals. The renal and neuroectdermal tumors are known as representative lesions by transplacental exposure to ENU in the offspring animals. However, little information is available about tumorigenicity in other organs and tissues in offspring when their mother animals are treated with ENU during gestation. Thus, the purpose of this study was to evaluate the effects of transplacentally treated-ENU on the various organ tumorigenicity in offspring rats. ENU was injected intraperitoneally to female Sprague-Dawley (SD) rats with a single dose at 50 mg/kg on the 18th day of gestation. After spontaneous delivery, 44 male and 64 female offspring, including moribund and dead after birth, were subjected to the evaluation of carcinogenicity. At the 54th to 55th week of birth, all surviving offspring were euthanized under ether anesthesia for histopathology. ENU showed a wide spectrum of transplacental tumorgenesis in the kidney, central nervous system, peripheral nervous system, thyroid gland, and teeth. The tumors of the thyroid and teeth were characteristic in particular in this study. The thyroid tumors included various histopathological types (follicular cell adenoma and adenocarcinoma, C-cell adenoma and carcinoma, squamous cell carcinoma, and fibroma). As a characteristic tumor of the teeth, ameloblastic odontoma was detected in 3 (one male and 2 females) of 108 offspring. In conclusion, the results indicate that the transplacental exposure of a single ENU dose induces various types of thyroid gland tumors and odontogenic tumors as well as the renal or neuroectodermal tumors in rat offspring. (J Toxicol Pathol 2004; 17: 7-16)

Evaluation of trans-1-amino-3-18F-fluorocyclobutanecarboxylic acid accumulation in low-grade glioma in chemically induced rat models: PET and autoradiography compared with morphological images and histopathological findings

“…Lesions for protocol 1 were required to measure at least 3 mm in the smallest dimension, while lesions for protocol 2 were required to be located at least 0.75-mm deep to the cut surface on histological section. Gliomas for each protocol were classified according to their histopathological features [14,15] and the degree of anaplasia, invasiveness, hemorrhage, and necrosis [16].…”