Objective: To observe the effects of total flavones of Epimedium leptorrhizum Stearn (YYH-C) on rat osteoporosis induced by retinoic acid. Method: Rats were divided into control group

model group

Xianling Gubao capsule group(0.3 g·kg-1)and YYH-C lower

middle

and high dose (raw materials 0.7

1.4

2.8 g·kg-1) groups. Except the control group

each groups were administrated retinoic acid 70 mg·kg-1 in the first 14 consecutive days. At the same time

the different treatment groups were given the corresponding drug to intervene for 28 days. The vertebrae bone and femur bone of left side were dissected to examine the parameters of bone

including bone mineral density (BMD)

bone Ca

bone P

and ash weight/dry weight percentage;the femur bone of right side were dissected to assess the morphology of bone. Result: After 28 days

the BMD of vertebrae bone and ash weight/dry weight percentage of femur bone of the model rats were obviously lower

compared with control group(P<0.01

P<0.05). Ca and P content of bone of the model rats were also significantly lower than those of control group(P<0.01). Morphological examination showed osteoporosis performance such as femoral cortical thinning

bone marrow cavity enlargement

the trabecular bone becaming thin

sparse and irregular

moreover

osteoblast number reduced. YYH-C 2.8 g·kg-1 group could significantly increase the BMD and ash weight/dry weight percentage of vertebrae bone(P<0.01

P<0.05)

meanwhile

three treatment groups of YYH-C could increase the ash weight/dry weight percentage and Ca

P content of the bone

enlarge trabecular area and cortical bone area percentage(P<0.01

P<0.05). In addition

YYH-C 1.4

2.8 g·kg-1 groups could increase the thickness and area percentage of trabecular bone (P<0.01)

YYH-C of 1.4 g·kg-1 could reduce the number of osteoclasts (P<0.05). Conclusion: The total flavones of E. leptorrhizum Stearn could resist osteoporosis on rat effectively by preventing the loss of bone mass on rat caused by retinoic acid

improving the microstructure of bone tissue

regulating the disorder of bone formation and bone destruction.