Diet composition but not rat source affects bone quantity and strength in rats with subclinical inflammation

Abstract

Previous studies have shown differences in sensitivity to colon carcinogens among similar strains of rats from different suppliers, suggesting differences in colonic inflammation and epithelial cell proliferation. It is unclear if these differences may affect bone health differently. We determined if rats from different suppliers fed either control or experimental diet would have different bone mineral content (BMC), bone mineral density (BMD), and bone strength. Male Wistar rats (supplier was Harlan or Charles River, n = 12/group) were randomized to control diet (AIN‐76A, carbohydrate as glucose) or an experimental diet (AIN‐76A, carbohydrate as fructose as well as high iron, low calcium). Left femur (LF) and lumbar vertebrae (LV) were collected after 11 weeks of feeding. BMC and BMD of LF and LV were measured using DEXA. Peak load (PL), the maximum force a bone can withstand before fracture, was measured by 3‐point bending (LF) and compression (LF neck, LV3). The experimental diet resulted in lower (P <0.001) BMC and BMD of LF and LV, and lower (P <0.001) PL at all three sites, regardless of rat source. There was an interaction of rat source and diet in which Harlan rats fed control diet had higher (P < 0.05) PL at the LF neck than Charles River rats fed control diet. These results suggest that rat source and differences in subclinical inflammation are lesser determinants of bone quantity and strength than diet composition.