Relationship between Bone Morphological Microstructure and Inflammatory Markers in Growing Mice Fed a High Fat Diet

ABSTRACT

Obesity not only reduces bone mineral density but also increases inflammatory markers. Therefore, we examined the change in inflammatory markers and morphological microstructure of the bones using a mouse model fed a high-fat diet. C57BL/6J 4-week-old male mice were divided into a control group (n = 6) and a experimental group (n = 6); the control group was provided with 10% Kcal fat diet, and the high-fat diet group was provided with 45% Kcal fat diet for 12 weeks using the free provision method. Blood was analyzed for inflammatory markers, and micro-computed tomography was used to measure the morphological microstructure of the femoral bone. The weight increases in the control group and high-fat diet group were 5.85 +/- 1.84 g and 16.06 +/- 5.64 g, respectively (p < 0.01), glucose was 115.00 +/- 16.88 mg/dL and 188.33 +/- 13.29 mg/dL (p < 0.01), and triglycerides were 65.00 +/- 6.19 mg/dL and 103.33 +/- 8.02 mg/dL (p < 0.05) respectively. Leptin and interleukin (IL)-6 were significantly higher in the high-fat diet group than that in the control group (p < 0.01). As a result of a biochemical index analysis of bone metabolism, osteocalcin tended to be lower in the high-fat diet group, whereas CTx was significantly higher in the high-fat diet group compared to that in the control group (p < 0.01). The thickness of the bony trabecula was significantly narrower in the high-fat diet group than that in the control group (p < 0.05), and the gap in the bony trabecula was significantly wider in the high-fat diet group than that in the control group (p < 0.05). IL-6 and the gap in the bone trabecula, which was a morphological microstructure of the bones, showed a positive correlation (p < 0.05). Taken together, inducing obesity through a high-fat diet in mice during the growth phase caused a change in bone microstructure and was correlated with the inflammation index. Accordingly, restriction of excessive fat intake may be needed to suppress the inflammatory reactions and promote normal bone formation.