Influence of dietary lipids and vitamin E on bone modeling, lipid peroxidation and chondrocyte function
Abstract
Three experiments were conducted to determine: (1) effects of dietary lipids on the fatty acid composition of growth cartilage, chondrocytes, and matrix vesicles (MV); (2) effects of dietary lipids and vitamin E (VIT E) on lipid peroxidation in tissues and on growth cartilage and trabecular bone formation; and (3) effects of supplemental fatty acids and VIT E on lipid peroxidation and cell function in primary cultures of epiphyseal chondrocytes (EC). Data from experiment one indicated that the fatty acid composition of cartilage was modified by dietary lipids varying in their total content of n-6 and n-3 polyunsaturated fatty acids (PUFA), saturated fatty acids or trans 18:1 fatty acids. All growth cartilage, EC, and MV contained high levels of saturated and monounsaturated fatty acids. Chicks given n-3 PUFA had significantly higher concentrations of 20:5n-3 and 22:6n-3 in cartilage and chondrocytes. Mead acid (20:3n-9) was found in the lipids of cartilage, EC and MV of all chicks, and the content of Mead acid was not affected by dietary linoleate (n-6 PUFA). Data from experiment two demonstrated that thickness of the mineralized zone in growth plate cartilage was increased significantly in chicks fed 90 IU/kg of VIT E compared to chicks fed 30 IU/kg of VIT E. Kinetic parameters on bone histomorphometry indicated that mineral apposition rate was higher in chicks fed 90 IU/kg of vitamin E. The interaction effect between VIT E and butter oil treatments led to the highest trabecular bone formation rate in chicks among the treatment groups. Experiment three evaluated the effects of iron-induced oxidative stress, supplemental fatty acids and vitamin E on lipid peroxidation, cellular injury, and collagen synthesis in primary cultures of avian EC. The activity of lactate dehydrogenase (LDH), indicative of membrane damage, was the highest and collagen synthesis was the lowest in chondrocyte cultures treated with 50 $\mu$M linoleic acid and no vitamin E. However, vitamin E supplemented at 100 $\mu$M lowered LDH activity and partially restored collagen synthesis in chondrocytes enriched with linoleic acid. VIT E reduced cellular lipid peroxidation in cartilage and linoleic acid induced cellular injury and impaired chondrocyte cell function. This research suggests that dietary lipids affect the fatty acid composition of cartilage tissues and chondrocyte function. Further, VIT E appears to be important in chondrocyte biology and beneficial to growth cartilage and bone development.
Degree
Ph.D.
Advisors
Watkins, Purdue University.
Subject Area
Food science|Livestock|Nutrition
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