Changes of bone lipid composition in oxidative stress

Abstract

Introduction: Composition and bone metabolism is of particular interest due to high incidence of osteoporosis, frequent and serious complications of the disease and increased risk of death after osteoporotic fractures. The aim of the research: Was to study the bone lipid composition in experimental oxidative stress induced by CCI4 long term administration. Materials and method: The study was conducted on a sample of 60 white laboratory rats of both sexes without pedigree. The animals were divided according to their age in 3 groups, each one consisted of 2 subgroups - control and with experimental oxidative stress. The level of total lipids, phospholipids, triglycerides, cholesterol (total, free and esterified) and total antioxidant activity were determined in the bone. Results: Our studies had revealed ontogenetic and gender dependent changes of the bone lipid content in oxidative stress. In young male rats significantly decreased the amount of phospholipids (11%, p<0,001) and triglycerides (45%, p<0,05), while in female one - the content of phospholipids increased by 8% (p<0,05) and that of cholesterol - decreased by (36%, p<0,05). The oxidative stress did not induce important changes in lipid concentrations in bone of adult animals. An exception is the reduction of phospholipid concentration by 24% (p<0,001) and the increase of the esterified cholesterol level by 39% (p<0,01) in males. Oxidative stress did not induce any changes of the lipid content in bone in old animales. At this developmental stage were influenced only the concentration of total cholesterol (+13%, p<0,05) and phospholipids (-12%, p<0,05) in male rats. In experimental oxidative stress induced by long term CCL4 intoxication ambiguous changes of total antioxidatn activity were found in animals of different age and gender, but in all cases the total antioxidatn activity was significantly higher then in the polar compartment compared in all studied groups. Conclusions: In oxidative stress, regardless of the ontogenetic stage of development, the amount of total lipids did not change conclusively, but the general trend was of decreasing, especially due to the reduction of phospholipids and triglycerides levels and less of cholesterol. Deeper disturbances of the saponifiable lipids content may be a consequence of the intensification of lipid peroxidation in bone, due to the production of free radicals during the carbon tetrachloride metabolism which affect predominantly the unsaturated fatty acids of the bone lipids.