Comparison of Spontaneous Minor Lesions in Wild-caught and Laboratory-bred Monkeys

抄録

We scrutinized the spontaneous histological lesions in 161 wild-caught cynomolgus monkeys (89 males and 72 females, age unknown) and 166 laboratory-bred rhesus monkeys (78 males and 88 females, from 3 to 5 years old) used in toxicity studies conducted at our laboratory. Various spontaneous lesions were observed in most of their organs. In the wild-caught monkeys, infestant lesions such as parasitic abscess and sarcocystis were mainly observed. On the other hand, in the laboratory-bred animals, the infestant lesions were rarely observed ; but edema in the renal papilla with or without intracellular edema of the papillary epithelium and gastritis associated with atrophy of the epithelium were observed frequently. The papillary lesions in the laboratory-bred animals were similar to the early changes of papillary necrosis or hyperplasia induced occasionally by drugs. It is generally considered that less variable data in hematology and biochemistry are obtained in laboratory-bred monkeys because the incidence of infectious or infestant lesions in them is less is less than that in wild-caught animals ; however, the spontaneous minor lesions were still observed frequently in the laboratory-bred animals. Furthermore, some spontaneous lesions even show histological similarity to the early lesions induced by drugs. Therefore, it is important to know the histological character of spontaneous lesions as well as their incidence for the pursuit of accurate evaluation of drug-induced toxicities in monkeys.