The effect of dietary lipids on bone turnover and skeletal growth in rats.

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07457509
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 矯正・小児・社会系歯学
• Research Institution: HIROSHIMA UNIVERSITY
• Principal Investigator: MORIMOTO Yuko Hiroshima university, School of dentistry, Orthodontic department, Research associate, 歯学部, 助 (20223422)
• Project Period (FY): 1995 – 1996
• Keywords: Dietary lipid / n-3 polyunsaturated fatty acids / Arachidonic acid / Prostaglandin / Bone histomorphometry / Growth / Osteoclast / Experimental tooth movement

Research Abstract

Fish oil-enriched diet, rich in n-3 polyunsaturated fatty acids, reduces the production of arachidonic acid and prostaglandins which mediate bone resorption. This study was conducted to investigate the effects of fish oil-enriched diet on bone turnover, skeletal growth and alveolar bone resorption incident to experimental tooth movement. Sixty 4-week-old male Wistar strain rats were divided into experimental and the control groups. Each group was fed purified diets containing 10 % fish oil and 10 % corn oil, respectively. Eight rats from each group were terminated at 2,4,6,8,10,14,18,22 and 26 weeks, and the proximal tibia and the mandibular condyle were examined by bone histomorphometry. Additionally, after 6-week feeding of the diets, the maxillary first molars were moved to the buccal direction, and bone resorption on the pressure side was evaluated.
1.In the proximal tibia, osteoclast number and bone resorption of the experimental group decreased to 60-80% of the controls in the primary spogiosa after 6 weeks. In the secondary spongiosa, they decreased to 40-60% and 65-75%, respectively. Longitudinal growth rate increased to 117% and 140% at 10 and 14 weeks, respectively. Bone formation was slightly increased at 10 weeks. In the condyle, osteoclast unmber and bone resorption decreased to 70-85% after 6 weeks. Longitudinal growth rate increased to 130% of at 8 and 10 weeks. The data suggest that fish oil-enriched diet has the effects of suppressing osteoclastic activity and bone resorption, and hastening longitudinal growth slightly.
The amount of tooth movement of the experimental group was 80.0 % of the controls, and osteoclast number and bone resorption on the pressure side decreased to 60 % and 80 %, respectively. The data suggest that fish oil-enriched diet delays experimental tooth movement by inhibiting osteoclastic activity and the subsequent bone resorption.