Withthe improvement of living standard and increase of life-span, osteoporosis has become oneof the most important diseases which affected living quality of old people, especiallypostmenopausal women. There are many difficulties in prevention and cure of the diseasefor its various causes and complex mechanism. At the present, it has been 30 years sincefluoride was first used to cure osteoporosis in 1964, its clinic application has beengenerally affirmed and fluoride plus calcium was was has been applied to cure ofosteoporosis,but some controversies still exist about it^{[ 1]} . The aim of the study is to evaluate the effect offluoride and fluoride plus calcium was on osteoporosis from oxidation and antioxidation,after different dose fluoride and fluoride plus calcium was given to ovariectomized ratsand to observe the serum LPO change.

1 MATERIALS AND METHODS

Sixty-fourfemale Wistar rats of three months (210±10)g were randomly divided into eightgroups.(1)in sham group:sham operation was carried on.(2) in OVX group:ovary resection wascarried on.(3) in OVXF₂ group,OVXF₄ group and OVXF₆ group:afterovary resection,fluoride-added water was given once every other day, the fluorine ioncontent in water was 2mg, 4mg, 6mg per liter.(4) in OVXF₂ Ca group, OVXF₄ Ca group and OVXF₆ Ca group: after ovary resection fluoride was given in thesame way as in OVXF₂ ,OVXF₄ and OVXF₆ group,simultaneouslywith calcium gluconate in each group,calcium ion content in water was 900mg perlitter.Animals of different groups were feeded in different cages with plenty of standardrat food, sufficient light and the temperature of (18±2)℃ .After six months,all animals were killed in respectivegroups,with blood from femoral artery in tube, then serum separated from blood,and serumLPO tested by TBA assay.The results date was analyzed with t test.

2 RESULTS

Theresults were as following.The different dose fluoride and fluoride calcium have effect onserum LPO in ovariectomized rats.As statistics showed in each group of 8 rats:the serumLPO(μ mol/L) wasrespectively:2.63±0.78 in sham group;3.25±0.75 in OVX;1.45±0.21 in OVXF₂ ;1.73±0.48in OVXF₄ ;1.26±0.28 in OVXF₆ ;1.52±0.190 in OVXF₂ Ca;1.54±0.46in OVXF₄ Ca;1.49±0.29 in OVXF₆ Ca.
2.1 In OVX group, theserum LPO was higher than that in sham group, after statistic analysis, a significantdifference was showed between the two groups (P< 0.05).
2.2 After ovaryresected,different dose fluoride and different dose fluoride plus calcium were given tothese animals ( OVXF₂ , OVXF₄ , OVXF₆ , OVXF₂ Ca,OVXF₄ Ca, OVXF₆ Ca group). Serum LPO in these groups was obviouslylower than that in only ovary resected group. After statistic analysis, there was asignificant difference (P< 0.01).
2.3 After ovary resected, different dose of fluoride was given in these groups compared with those groupsgiven with different dose of fluoride plus calcium, there was no obvious change in LPO.After statistic analysis, no remarkable difference was revealed(P> 0.05 ).

3 DISCUSSION

Lipidperoxidation is caused by polyunsaturated fatty acid in biological membrane phospholipidattacked by the free radical, which is produced by the body's enzyme system and non-enzymesystem. The injury of lipid peroxidation on cells lies chiefly in the injury of membraneunsaturated fatty acid, which leads to membrane dysfunction and injury of membrane enzymeas well as the injury of free radical resulting from lipid peroxidation on enzyme andother components of human body. In normal physical condition many antioxidant exist inliving things to prevent free radical injury, including antioxidase,fat-soluble antioxygen, small molecule water-soluble antioxygen, proteinic antioxygen and so on. Theycontinuously clear away free radical and form an intact antioxygen system to defend,prevent, block and renovate injury in different levels. Estrogen is the kind of steroidhormones with extensive biological activity. It can not only promote and maintain thedevelopment of female genital organ and secondary sex characters, but also have extensivepharmacological action on organism metabolism, endocrine, reticuloendothelial system,cardiovascular system and skeletal growing system. It was reported that female estrogenmay act against oxidation and another report said that estrogen decreased, and serum LPOincreased in menopause women, but correlation analysis showed that there was negativerelation between them, according to other reports the content of female serum lipidperoxide was lower than that in male, the same conclusion was reached in animal experiment^{[ 2]} . This study showed that serum LPO of ovariectomized ratswas much higher than that in sham operated group, probably due to estrogen deficiency inovariectomized rats, capability to clear out lipid peroxide decrease, and LPO increased inhuman body. Up to now, the mechanism of action remains unknown and further research isneeded.
Osteoporosis is akind of metabolic disease characterized by decrease in bone mass, change in microstructureof bone tissue and increase of the fracture risk. Complex causes exist in postmenopausalosteoporosis such as estrogen deficiency of postmenopausal, calcium regular hormoneimbalance and other dangerous factors, for example, calcium deficiency etc. In thisexperiment, ovariectomized rats were used as osteoporosis model was to observe the effectof fluoride and fluoride plus calcium on serum LPO. Fluoride was used to deal withosteoporosis by stimulating osteoblast mitogenesis to form bone. But it was invalid insome patients, the over-dose would effect bone mineralization and wove bone formed and ithad great effect on cancellous bone formulation, while no effect on cortical bone and soon. So some controversies still exist about its effection to cure osteoporosis^{[ 3]} . Calcium is an important chemical element to maintain thenormal physical function of circulatory, respiratory, nervous, digestive, endocrine,muscular, skeleton and immune system. Calcium chiefly distributes in human body,not onlyto maintain the physics intensity of skeleton in human body mainly, but also to keepmotional balanc with soluable calcium in circulation system. Riggis' research showed thatfluoride plus calcium compared with fluoride alone did better in increasing bone densityand decreasing fracture rate^{[ 4]} . Dure-Smith， research proved the effect of fluoride on axial bone wassignificantly better than that on periphery bone . If enough calcium was given intreatment of osteoporosis, both axial bone and periphery bone density would be improved^{[ 5]} . No report was given about effect of fluoride andfluoride plus calcium on occurrence, prevention and therapy of osteoporosis in oxidationand antioxidition. Our experiment showed that ovariectomized osteoporosis rats were givendifferent dose fluoride-added water once every other day and different dose fluoride andcalcium-added water in respective groups. After six months feeding, rat serum LPO wassignificantly lower than that in only ovary resection group, so was the LPO in thesegroups compared with sham operated group. It showed that after fluoride and fluoride pluscalcium given, the lipid peroxidation degree decreased in ovariectomized rats. But therewas no distinct difference in the serum LPO between group given fluoride alone and groupgiven fluoride plus calcium united. It was pointed out in our experiment condition thatafter the fluoride and fluoride plus calcium used the serum LPO decreased greatly(compared with sham operated group) in some degree, so no cooperating action showed afterfluoride and fluoride plus calcium united given. We inferred that fluoried and fluorideplus calcium may improve the antioxidation capability of human body, but its mechanisimremained unclear, and further study is needed.■

作者单位： ZHAO Ya-jun 赵雅君( Department ofPathophysiology,Harbin Medical University;)； LI Quan-feng 李全凤( Department ofPathophysiology,Harbin Medical University;)； JIANG Xiao-shu 姜小姝( Department ofPathophysiology,Harbin Medical University;)； YAN Jing-long 阎景龙( .Department ofOrthopedics,The Second Affiliated Hospital,Harbin Medical University,Harbin 150086,China)；

REFERENCES：

[ 1] Brown EM.Fluoride and the therapyof osteoporosis[ J] .J Clin EndocrinolMetab,1989,69:929.
[ 2]王钢编著 .自由基与中医中药[ M] .南京大学出版社， 1993.262.
[ 3] Erey H.Fluoride in the treatmentof osteoporosis[ J] .Acta Med Scand,1986,220:193-194.
[ 4] Riggs BL,Fallon WM,Lane A,etal.Clinical trial of fluoride therapy in postmenopausal osteoprotic women:extendedobservations and additional analysis[ J] .J Bone Miner Res,1994,9:265-275.
[ 5] Dure-Smith BA,Farley SM,LinkhartSG,et al.Calcium deficiency in fluoride-treated osteopotic patients despite calciumsupplementations[ J] .J Clin EndocrinolMetab,1996,81:269-295.

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