Cross-sectional analysis of intermittent versus chronic caloric restriction in the TRAMP mouse.
BACKGROUND
Previously we found that intermittent calorie restriction (ICR) delayed the age of prostate tumor detection and death in TRAMP mice in comparison to chronic calorie restricted (CCR) and ad libitum fed (AL) TRAMP mice.


METHODS
In the present study the same protocol was used in a cross-sectional experiment whereby mice were either ad libitum fed, intermittently calorie restricted at 50% of the consumption of AL mice for 2 weeks followed by 2 weeks of refeeding matched to AL intake or were pair-fed to the ICR. Both ICR and CCR protocols resulted in a 25% reduction in caloric intake. Mice were enrolled in the study at 7 weeks of age to be euthanized at designated time points in cycles 3, 6, and 9 with mice euthanized at the end of restriction and refeeding.


RESULTS
At the youngest time point in cycle 3 ICR impacted body weight, fat pad weights and serum factors the most. Additionally, the incidence of detectable prostate cancer pathology was reduced for ICR mice compared to AL and CCR mice. However, by cycle 5 when the mice were 28-30 weeks of age all mice except one ICR mouse had pathologically confirmed prostate cancer. Furthermore, at the two older time points many of the mice assigned to the study did not survive to reach their designated endpoints.


CONCLUSIONS
Overall these findings are consistent with other studies indicating protective effects of various interventions on the development of prostate cancer in young TRAMP mice.
Bonorden
Melissa J L
MJ
The Hormel Institute, University of Minnesota, Austin, Minnesota 55912, USA.
Rogozina
Olga P
OP
Kluczny
Christina M
CM
Grossmann
Michael E
ME
Grande
Joseph P
JP
Lokshin
Anna
A
Cleary
Margot P
MP
D000230:Adenocarcinoma / Q000473:pathology / Q000503:physiopathology* / Q000517:prevention & control*; D000273:Adipose Tissue / Q000033:anatomy & histology; D000367:Age Factors; D000818:Animals; D001835:Body Weight; D031204:Caloric Restriction; D003430:Cross-Sectional Studies; D004195:Disease Models, Animal; D004435:Eating; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009929:Organ Size; D011471:Prostatic Neoplasms / Q000473:pathology / Q000503:physiopathology* / Q000517:prevention & control*