Effect Of Hyperlipidemia Induced By High-fat Diet On Bone Healing In ApoE Gene Deficient Mice

Introduction:Cardiovascular diseases (CVD) are closely associated with bone loss diseases such as periodontitis, with hyperlipidemia serving as one of the common etiological factors of both diseases. The study established hyperlipidemia model by giving atherogenic high fat diet to apoE-/-mice, to clarify the exact effect of hyperlipidemia on bone regeneration in mandibular bone defect.Materials and methods:7week-old male ApoE-/-and wildtype(WT) mice on the background of C57BL/6J were fed with the same atherogenic high-fat diet(HFD) for6weeks and WT mice served as control. Then operations were performed to create bone defect (1.5mm in diameter) in the buccal surface of mandibular bone below the first molar of mice in both groups.8or16days after surgery, serum was isolated to measure the level of serum lipid, and mandibles were harvested for micro-CT and bone morphometric analysis.Results:After fed with the atherogenic HFD, apoE-/-mice showed dramatically elevated serum levels of total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-c) and low-density lipoprotein-cholesterol (LDL-c) compared with the WT mice. Bone regeneration in apoE-/-mice was considerably delayed, appeared as lower amount of new bone and delayed bone generation and mineralization in apoE-/-mice as shown by micro-CT analysis and bone morphometric analysis.Conclusions:A successful animal model of hyperlipidemia is established by feeding the apoE-/-mice with atherogenic HFD. Our results clearly indicate that bone regeneration and mineralization in mandibular bone defect region are disturbed in animals with elevated serum lipid levels.