After one week of isolation, seven-week old male A/J mice (n=25) weighing 17-19 g, were randomly divided into three groups: Group A (n=5), Group B (n=10), and Group C (n=10). Mice in groups B and C were each given a single intraperitoneal injection of urethane (1 mg/g body weight) in saline, while Group A mice received an injection of saline alone. Groups A and B were fed a regular diet, while Group C was fed the same diet supplemented with 0.5% NM. After 20 weeks, mice were sacrificed, lungs were excised and weighed, and tumors were counted and processed for histology. Mice in urethane-challenged mice developed tumors; however, the mean number of tumors and the mean lung weights in the supplemented mice were significantly reduced, by 49% (p<0.0001) and 18% (p=0.0025) respectively, to mice on the control diet. Pulmonary lesions were morphologically similar for both the groups (adenomas) but lesions were smaller in the test group. These results suggest that NM has inhibitory potential on the development of mouse lung tumors induced by urethane.
A/J mice, nutrient mixture, primary lung tumors, urethane
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