Establishment and assessment of rat models of glucocorticoid-induced osteonecrosis / 中国医学科学院学报

ABSTRACT

<p><b>OBJECTIVE</b>To establish the rat models of glucocorticoid-induced osteonecrosis and evaluate the osteonecrosis by high-resolution micro-CT and histomorphology.</p><p><b>METHODS</b>Totally 30 Sprague-Dawley male adult rats (age12 weeks; body weight400-450 g) were randomized into two groupsone group received two doses of intraperitoneal injection of lipopolysaccharide (20 μg/kg) at an interval of 24 hours, 24 hours later, the rats received three doses of intramuscular injection of methylprednisolone (40 mg/kg) at an interval of 24 hours; in the control group,the rats received same amount of normal saline. Four weeks later, 5 rats in each group were sacrificed randomly.Eight weeks later, all the remaining rats were sacrificed and the femur specimens were scanned by micro-CT. The trabeculae parameters of the femoral head were calculated. The hematoxylin and eosin staining were performed to calculated the success rate.</p><p><b>RESULTS</b>The incidence of osteonecrosis was 80% in the experimental group. The micro-CT demonstrated broken and cystic degeneration. The quantitative analysis showed that the bone volume/total volume (experimental group0.55 ± 0.13 vs.</p><p><b>CONTROL GROUP</b>0.68 ± 0.12;P<0.05), bone surface area / bone volume (experimental group20.45 ± 5.13 vs.</p><p><b>CONTROL GROUP</b>24.00 ± 5.20;P<0.05), and trabeculae number(experimental group 5.67 ± 0.50 vs.</p><p><b>CONTROL GROUP</b>6.24 ± 0.96; P<0.05) were significantly lower in experimental group than those in control group.</p><p><b>CONCLUSIONS</b>A rat model of glucocorticoid-induced osteonecrosis was successfully established by lipopolysaccharide and methylpredniso- lone. High-resolution micro-CT is useful for the qualitative and quantitative analyses of the morphology and structure of trabeculae, showing good consistence with the histomorphological findings.</p>