Effect Of Total Flavonoids Of Herba Epimedii On The Apoptosis Of Cells In The Bone Of Ovariectomized Rats

Objective: To investigate the effect of total flavonoids of Herba Epimedii (HEF) onthe apoptosis of osteoblasts and osteocytes in the bone of ovariectomized rats.Toelucidate the mechanism of HEF in preventing and treating postmenopausalosteoporosis.Methods: Fifty-four female rats were allocated into 6 groups, 9 ineach;ovariectomized (OVX)group, sham operation group, OVX followed by threedoses of HEF (40,80 and 160mg·kg-1) and nilestriol (0.1 mg·kg-1)for 12 weeksrespectively. Bone mineral density (BMD) of whole body of rats was determined byDEXA. The levels of osteocalcin and estradiol in serum were measured by radioimmunologic method. The apoptotic cells(steoblasts and osteocytes) were examinedby transmission electron microscope and with TUNEL technic.At the same time,theexpression of TGF-β1,FGF-2 protein and apoptosis controlling gene Fas proteinwas determined by immunohistochemical method.Results: The level of serum E2 and BMD of whole body in the OVX group werelower than those in sham group significantly after 12 weeks(P＜0.05). Compared withthe OVX group, the BMD and the level of BGP in the HEF (160mg·kg-1) groupwere increased (P＜0.05),but the level of serum E2 was not increased(P＞0.05).TUNEL examination showed:compared with other groups, OVX groupmarkedly significantly increased the apoptosis of osteoblasts and osteocytes,therewere significantly difference(P＜0.01).HEF stimulation attentuated apoptosis ofosteoblasts and osteocytes, the apoptosis of osteoblasts in the HEF (160mg·kg-1)group were significantly lower than those in the sham rats.As for the apoptosis theosteocytes,No matter E2 group or HEF(80 and 160mg·kg-1) group,the apoptosis ofosteocytes were significantly lower than the sham group,there were significantlydifference(P＜0.05).The Fas protein examination demonstrated that OVX groupslightly higher than sham group and no difference between OVX group and shamgroup(P＞0.05),HEF(40,80 and 160mg·kg-1) group and E2 group significantly lower than OVX group(P＜0.01),Furthermore,compared with sham group, HEF(40,80 and160mg·kg-1) group were significantly reduced(P＜0.05). TGF-β1 is expressed inactively synthesizing osteoblasts, flattened lining osteoblasts,osteocytes,chondrocyted,and mesenchymal cells,and bone matrix,the expression of TGF-β1 in the OVX wereslightly lower than sham group, HEF(40,80 and 160mg·kg-1) group and E2 groupsignificantly increased than OVX group(P＜0.01).Compared with OVX group,theexpression of FGF-2 on sham group, HEF(40,80 and 160mg·kg-1) group and E2group were dignificantly increased(P＜0.01), HEF(160mg·kg-1) group were higherthan sham group(P＜0.05)Conclusion: we conclude that HEF are useful in the treatment of postmanupausalosteoporosis resulting from ovariectomy, what the HEF stimulation,elevating theexpression of TGF-β1 and FGF-2 protein,and restraining Fas protein expression inosteoblasts and steocytes,attenuating osteoblasts and osteocytes apoptosis may be oneof the possible mechanisms of therapeutic efficacy of postmanupusal osteoporosis.