Objective: To investigate the bone repair effect of Bushen formula on rats with steroid-induced osteonecrosis of the femoral head(SONFH). Method: Male Wistar rats were randomly divided them into 6 groups:control group

model group

high-dose Bushen formula

mid-dose Bushen

low-dose Bushen groups

and Jiangusheng pills group. Then gluteal injection with methylprednisolone sodium succinate by 21 mg·kg-1 into all rat groups except for control group

once a day

for 3 consecutive days was conducted to establish the model of SONFH. Since the fourth day

low-dose Bushen

Mid-dose Bushen

High-dose Bushen groups and Jiangusheng group were give 5.3

10.6

21.2 g·kg-1 Bushen formula and 1.68 g·kg-1 Jiangusheng pills respectively. Six weeks later

their blood and femoral head were collected to observe the histopathological changes of femoral head by HE staining. Micro-CT scanning was used to observe femoral bone morphogenetic changes and analyze the bone morphometry. Bone metabolism markers osteocalcin(bone gla-protein

BGP) and calcitonin(CT) content were detected by ELISA. Result: The femoral head of model group rats showed many histopathological changes

such as more empty lacunae

more fat cells

narrowed or broken bone trabecula

the bone marrow cavity cytopenia

massive necrosis zones. Besides

femoral head collapse

osteopenia

trabecular thinning and other imagological changes can also be observed. According to the bone metrological parameters

bone volume fraction

trabecular thickness

trabecular bone pattern factor

trabecular number and bone density decreased

but trabecular separation increased in model group rats. BGP and CT content in serum significantly reduced in model group rats. Compared with the model group

mid-dose and high-dose Bushen can significantly improve the pathological changes in femoral head of rats. The three dose Bushen groups showed significant inhibition of bone necrosis. Mid-dose and high-dose Bushen can remarkably increase BGP and CT content in serum. The Jiangusheng group had a similar effect with mid-dose Bushen group. Conclusion: Bushen formula can significantly improve the histopathological and imagological changes of rats with SONFH and increase BGP and CT content in serum. This effect in promoting bone repair may be one of its mechanisms of preventing steroid-induced femoral head osteonecrosis.