Establishment and assessment of rat models of glucocorticoid-induced osteonecrosis.
OBJECTIVE
To establish the rat models of glucocorticoid-induced osteonecrosis and evaluate the osteonecrosis by high-resolution micro-CT and histomorphology.


METHODS
Totally 30 Sprague-Dawley male adult rats (age:12 weeks; body weight:400-450 g) were randomized into two groups:one 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.


RESULTS
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 group:0.55 ± 0.13 vs.


METHODS
0.68 ± 0.12;P<0.05), bone surface area / bone volume (experimental group:20.45 ± 5.13 vs.


METHODS
24.00 ± 5.20;P<0.05), and trabeculae number(experimental group: 5.67 ± 0.50 vs.


METHODS
6.24 ± 0.96; P<0.05) were significantly lower in experimental group than those in control group.


CONCLUSIONS
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.
Department of Orthopedics, PUMC Hospital, CAMS and PUMC, Beijing 100730, China.
Yu-lei
YL
Dong
Department of Orthopedics, PUMC Hospital, CAMS and PUMC, Beijing 100730, China.
Lei
L
Zhou
Department of Orthopedics, PUMC Hospital, CAMS and PUMC, Beijing 100730, China.
Yu-long
YL
Li
Department of Orthopedics, PUMC Hospital, CAMS and PUMC, Beijing 100730, China.
Ke
K
Xiao
Department of Orthopedics, PUMC Hospital, CAMS and PUMC, Beijing 100730, China.
Xi-sheng
XS
Weng
D000818:Animals; D004195:Disease Models, Animal; D005270:Femur Head; D005271:Femur Head Necrosis; D005938:Glucocorticoids; D008070:Lipopolysaccharides; D008297:Male; D008775:Methylprednisolone; D051381:Rats; D017207:Rats, Sprague-Dawley
D005938:Glucocorticoids; D008070:Lipopolysaccharides; D008775:Methylprednisolone