الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The healing of bone defects remains a significant clinical orthopedic challenge. Autologous bone grafts are considered the gold standard. However, these procedures may cause donor-site morbidity, such as hemorrhage, infection, and chronic pain. Bone marrow harbors an abundant source of stem/progenitor cells, which participate in the regeneration of a variety of tissues following injury. Generation of progenitor cells from the bone marrow is one major response during tissue repair. Therefore, an alternative strategy for bone defect healing is to stimulate endogenous stem cell populations from the mature body and actively attract them to the sites of injury.
Statins, such as simvastatin, are specific, competitive inhibitors of 3-hydroxy-2-methyl-glutaryl coenzyme A (HMG CoA) reductase. They are widely used in prevention of cardiovascular disease and to lower cholesterol level.
In addition to the cholesterol-lowering effect, statins have a series of pleiotropic effects. Among these diverse effects, bone anabolism has been the focus of research for more than a decade. The suggestion that statins can increase bone formation has provided an exciting direction for research as well as providing a greater understanding of the biological importance of cholesterol synthetic pathways.
Summary and conclusion
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The aim of this study was to evaluate histologically and radiographically the bone healing after implantation of simvastatin in surgically created defects in long bones of rabbits.
In this study 28 defects (6 mm in diameter) were surgically created in fourteen adult male white New Zealand rabbits and randomly distributed into group I (study group) and group II (control group).
group I included 14 surgically created bony defects treated with simvastatin and equally subdivided into two subgroups each one included seven defects: group (IA) in which sacrifice was done after four weeks and group (IB) in which sacrifice was done after eight weeks.
group II included 14 surgically created bony defects in which no material was applied into these defects. It was equally subdivided into two subgroups each one included seven defects: group (IIA) in which sacrifice was done after four weeks and group (IIB) in which sacrifice was done after eight weeks.
The harvested tibiae were evaluated using radiographic and histological methods. CBCT was used to measure the surface area of the defects in mm2. Histomorphometric analysis of Goldner’s Trichrome stained sections was done to assess the newly formed osteoid. Results were collected, tabulated and assessed by independent samples t-test to assess statistical significance between the studied groups.
Summary and conclusion
60
Radiographic evaluation showed significant decrease in surface area of bony defects in the study groups at four and eight weeks compared with the control groups. Histomorphometric analysis showed significant increase of newly formed osteoid in the study groups at four and eight weeks indicating better bone healing.