The Expression Of ERα, TGFβ1, OPG, VEGF In The Bones Of Ovariectomized Rats And Its Significance

ObjectiveTo observe the local molecule expressions of TGF- β1 VEGF, and the local protein expressions of OPG ER α in tibias of ovariectomized rats, and after E2 treatment and 6 weeks 8 weeks after ovariectomized, ER α , OPG TGF-β 1 VEGF have changes of expressions ,we can study the following questions: (l)To explore the relationships between estrogen and ER α OPC TGF- β 1 VEGF;(2)To explore the relationships between ovx osteoporosis and ER α OPG TGF-β 1 VEGF, and explain the pathogenesis of ovx osteoporosis; (3)To explore the mechanics of estrogen treatment on ovx osteoporosis; (4)To explore in different times(6w 8w after ovx) ER α OPG TGF- β 1 VEGF influences on ovx osteoporosis, and influences on estrogen treatment on ovx osteoporosis.MethodsFifty-three female SD rats, six months, were randomly divided three groups: ovx(ovariectomized) group ,sham group and estrogen treatment. Every group had 8 rats. All rats were sacrificed by arteria cruralis bleeding at the end of 6w and 8w after ovx. We selected right tibias to observe histology , in situ hybridization of TGF- β 1 VEGF, and immunohistochemistry of OPG ER α by a microscope with grids.Results6w and 8w after ovx, we can see(1) ER α protein expression expressions:(1)ER α protein expressions in rat tibias are situated in cartilar cartilage cells,hypertrophic chondrocytes and proliferative chondrocytes of epiphysealplate ,osteoblasts,osteocytes, fibroblasts besides cortical substance ; and ERαprotein expressions in hypertrophic chondrocytes of epiphyseal plate are more thanproliferative chondrocytes;(2)1 n ovx groups ER α protein expressions in cartilar cartilage cells, hypertrophicchondrocytes of epiphyseal plate, mesenchymal cells in bone marrow aresignificantly less than those of sham groups(p<0.05 or p<0.01);(3) In ovx+E2 groups ER α protein expressions in above locations are significantlymore than those of ovx groups(p<0.05 or P<0.01). But ER α protein expressionsin mesenchymal cells 8w after ovx are significantly less than those of 6w afterovx(p<0.01);(4)No differences between 6w and 8w are ER α protein expressions in abovelocations;(5)ER α protein expressions of megakaryocytes in bone marrows 8w estrogentreatment after ovx are significantly more than those of 6w(p<0.05).(2) TGF- β 1mRNA expressions:(1) TGF- β 1mRNA expression are located in cartilar cartilage cells, hypertrophic chondrocytes and proliferative chondrocytes of epiphyseal plate ,osteoblast and mesenchymal cells in bone marrows; (2)In ovx groups TGF-β lmRNA expressions in above locations have a lesstendency than those of sham groups, and TGF- 3 lmRNA expressions in cartilarcartilage cells in ovx group are significantly less than those of shamgroup(p<0.05);(3)In 0VX+E2 groups TGF- P lmRNA expressions in cartilar cartilage cells,hypertrophic chondrocytes of epiphyseal plate, mesenchymal cells in bone marroware significantly more than those of ovx groups(p<0.05 or p<0.01);?No differences between 6w and 8w are TGF- P lmRNA expressions in abovelocations.(3)OPG protein expression expressions:?OPG protein expressions are mainly situated in cartilar cartilage cells,hypertrophic chondrocytes of epiphyseal plate, and cement line of primary bonetrabecula. Osteoblasts and osteocytes are weakly positive. Mesenchymal cells inbone marrow expressed very weak or no . And megakaryocytes are weaklypositive;? In ovx groups , OPG protein expressions in cartilar cartilage cells,hypertrophic chondrocytes of epiphyseal plate have a more tendency than those ofsham groups;(3)1 n 0VX+E2 groups, OPG protein expressions in above locations have a moretendency than those of ovx groups;?No differences between 6w and 8w are OPG protein expressions in abovelocations.(4)VEGF mRNA expressions status:?VEGF mRNA expressions are mostly situated in cartilar cartilage cells,hypertrophic chondrocytes and proltferative chondrocytes of epiphysealplate ,osteoblasts,osteocytes, and mesenchymal cells in bone marrows, especiallymegakaryocytes, and fibroblasts besides cortical substances;(2) In ovx groups VEGF mRNA expressions in cartilar cartilage cells,hypertrophic chondrocytes of epiphyseal plate and mesenchymal cells in bonemarrow have a more tendency than those of sham groups;?In 0VX+E2 goups VEGF mRNA expressions in cartilar cartilage cells,hypertrophic chondrocytes of epiphyseal plate have a less tendency than those ofovx groups.;?No differences between 6w and 8w are VEGF rnRNAexpressions in abovelocations.Conclusion:(1) Estrogen loss after ovx enabled ER a degrading through estrogen receptor mediated mechanism. Then TGF- P lmRNA expressions are decreasing which inhibits OCL apoptosis pathway is madiated by TGF- 3 1, so osteoclasts formation are enhancing. This mechanism is that TGF- P 1 induce OPG generation to interfere RANKL/RANK mediating osteoclast information in order to enhance bone resorption. Therefore, TGF- P 1 degrading may lower OPG to promote osteoclast foremation in bone resorption.(2) Estrogen defect after ovx may produce more VEGF to participate in bone angiopoietic process. And perhaps more angiopoiesis formate to participate in bone loss. Moreover, VEGF as osteoclasic chemotaxin may induce osteoclast bone resorption.(3) After estrogen treatment, all indexes retrieve to normal level so that estrogen...