An investigation of the mouse as a model for vincristine toxicity

The purpose of this study was to investigate the toxicologic responses of mice to vincristine (VCR), an established antitumor drug, and to compare them with those reported for dogs, monkeys, and humans. This comparison was expected to facilitate the continuing appraisal of the mouse as a model for toxicologic responses to antitumor drugs in human patients. In duplicate experiments, male B6D2F1 mice were treated with 1.0, 1.5, 2.0, and 3.0 mg/kg of VCR in single IP doses. These sublethal doses corresponded to 0.25, 0.40, 0.50, and 0.80 LD50. On posttreatment days 1, 3, 6, 10, 14, and 21, groups of mice were killed and blood and other tissues were collected for hematologic (8 tests), clinical chemical (15 tests), and histopathologic (11 tissues) evaluations. VCR produced dose-dependent body weight loss, reticulocytopenia, granulocytopenia, elevated plasma alkaline phosphatase, GPT, and GOT activities, and damage to the gastrointestinal epithelium. These reversible changes were most severe during the first 3 days posttreatment. The mouse was comparable to the dog and the monkey in reflecting the target organ toxicity of VCR in humans. Studies with additional antitumor drugs will be required before the overall predictive reliability of this model can be expressed quantitatively.