The The Effect Of Simvastatin On The Stability Of Micro-implant In Osteporosis New Zealand Rabbits

Objectives:Establishment of New Zealand rabbits osteoporosis model by ovariectomy-and dexamethasone .Investigate the effect of simvastatin on the stability of Micro-implant in osteporosis rabbits. To improve, stability of Micro-implant and Provide a theoretical and experimental basis.Methods:Twenty-one 5-mouth-old female New Zealand rabbits weighed about 2kg were randomly divided into three groups,Sham-operated group,(Sham) Ovariectomized group, (OVX)Ovariectomized and Simvastatin Therapy group (OVX+Simv). Every group have 7 rabbits . OVX group OVX+Simv group established model of osteoporosis by the ovariectomy plus 0.5mg/kg dexamethasone intramuscular injection twice a week . Only a few fatty tissues surround of ovaries is removed from Sham, then gave with equivalent normal saline. After the animal models of osteoporosis established,Implant two titanium screw Micro-implants into the Proximal metaphyses of tibiae of every rabbit. The spacing between the micro-implants is 2 cm. Aweek later. simvastatin was administered orally 10mg/kg/d to OVX+Simv group and saline to the other groups lasting 9 weeks. Two weeks after Surgery, two micro-implants in one bone were given 100g mutual extraction by nickel-titanium extension spring. The extraction was kept for 8 weeks .After 8 weeks, blood sample was collected from Ear vein to obtain levels of alkaline PhosPhatase(ALP), and bone graprotoin(BGP)at the time of killing. Measure the distance between micro-implant in the X-ray to calculate the amount of movement between the micro-implant. Three groups new zealand rabbits were put to death. After checking the bone density of the femurs, stripped the tibias with implants.Tibias with implants were fixed by formaldehyde to make the undecalcified cutting disc. Tibias with implants discs were stained by toluidine blue.The effect of simvastatin on the stability of Micro-implant in osteporosis rabbits. spss16.0 software used in this analysis. All results are used ( x士s).Using ANOVA analysis of the results.Results:1. 8 weeks after extraction between micro-implants, the largest moving distance between micro-implants of OVX group is 1.04mm.the second is OVX+simv 0.416mm The .third is Sham group only 0.322mm.2., 9 weeks after simvastatin administration, the BMD of femurs,BGP in three groups have differences.3. 9 weeks after simvastatin administration cancellous bone volume and micro-implants osseointegration rate of cancellous bone in three groups have differences. cortical bone volume, the micro-implants osseointegration rate of cortical bone in OVX+ Simv group have no difference with two groups, however OVX group and Sham group have difference.ConclusionSimvastatin have a role in improving the Bone formation.Simvastatin increase the mass of bone around implant and have a role in improving the osseointegration of pure titanium implants in rabbits with osteoporosis and reduce speed. Therefore, simvastatin can fight adverse effects of micro-implants in osteoporosis.