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Inhibition of intestinal tumorigenesis in methylazoxymethanol-treated rats by dietary restriction
Abstract:
Male Sprague-Dawley rats were inoculated once with methylazoxymethanol (MAM) and groups were fed restricted diets for the following 140 days: Group A or B was fed a 12-g diet daily (25% restricted) from Day 10 or Day 63 after MAM, respectively. Group C or D was fed ad libitum only every other day from Day 8 or Day 31 after MAM, respectively. Control MAM-treated rats were fed the same diet ad libitum. When examined at Day 140, there was a significant reduction of intestinal tumors in Group A on the restricted diet from Day 10; however, among all other groups there were no significant differences in tumor incidences. Later onset of daily dietary restriction or of feeding and fasting every other day did not change the pattern of tumorigenesis from that which developed in control rats fed ad libitum.
Insights
Early daily dietary restriction significantly reduced intestinal tumors in rats exposed to methylazoxymethanol (MAM). Later dietary interventions showed no significant effect on tumor development.
Area of Science:
- Oncology
- Gastroenterology
- Nutritional Science
Background:
- Methylazoxymethanol (MAM) is a carcinogen used to induce intestinal tumors in animal models.
- Dietary interventions are being explored as a strategy to mitigate cancer development.
Purpose of the Study:
- To investigate the impact of early-onset versus delayed dietary restriction on intestinal tumorigenesis induced by MAM.
- To evaluate the efficacy of daily caloric restriction and intermittent feeding regimens in preventing tumor formation.
Main Methods:
- Male Sprague-Dawley rats were administered MAM to induce intestinal tumors.
- Groups were subjected to different dietary regimens: daily 25% restriction starting on Day 10 or Day 63 post-MAM, or alternate-day feeding starting on Day 8 or Day 31 post-MAM.
- Control rats received MAM and were fed ad libitum.
Main Results:
- Early daily dietary restriction (starting Day 10 post-MAM) significantly reduced intestinal tumor incidence.
- Delayed daily restriction (starting Day 63) and alternate-day feeding regimens (starting Day 8 or Day 31) did not significantly alter tumor incidence compared to controls.
- The timing of dietary intervention critically influenced its effectiveness in reducing MAM-induced intestinal tumors.
Conclusions:
- Initiating daily dietary restriction shortly after carcinogen exposure can effectively suppress intestinal tumor development.
- Delayed dietary interventions or intermittent feeding patterns are less effective in preventing tumor formation in this model.
- These findings highlight the importance of early nutritional strategies in cancer prevention.