探討 isoflavone 和 ozagrel 對卵巢切除小鼠骨代謝的影響

The effects of isoflavone and ozagrel on bone metabolism in ovx mice

劉宜旻(Yi-Min Liu)

指導教授 ： 林淑容

中原大學/工學院/生物科技研究所/碩士(2011年)

https://doi.org/10.6840/cycu201101088

摘要

摘要

在人類遺傳性疾病 Ghosal hematodiaphyseal dysplasia syndrome (GHDD) 研究中發現患者因 thromboxane A2 synthase (TXAS) 基因發生突變，使 thromboxane A2 (TXA2) 產量減少，造成骨質密度明顯增高。因此，本研究進一步利用卵巢切除小鼠配合植物雌激素或 TXAS 抑制劑餵食，探討抑制 TXA2 合成及補充植物雌激素在卵巢切除母鼠之骨質密度維持上的效用及其可能之細胞內分子作用機制。實驗的方法是母鼠進行卵巢切除後，單獨餵食 isoflavone (含 35.51% Genistein 之大豆萃取物)、ozagrel (TXAS 抑制劑)，或同時餵食 isoflavone 與 ozagrel 八週。實驗結果發現卵巢切除母鼠之骨質密度明顯低於佯作手術之母鼠；而卵巢切除後餵食 isoflavone、ozagrel 或同時餵食 isoflavone 與 ozagrel 之小鼠，其骨質密度皆較卵巢切除且未餵食 isoflavone 與 ozagrel 之對照組小鼠顯著增加。顯示雌激素缺乏會造成骨質流失，而補充植物性雌激素或 TXAS 抑制劑可減緩骨質的流失。另外在維持骨質平衡之相關基因表達方面，單獨餵食 ozagrel 之小鼠，其 RANKL 基因表達及 RANKL/OPG 比值較卵巢切除之對照組小鼠為低。同時餵食 isoflavone 與 ozagrel 之小鼠，其 IL-6、RANKL 基因表達及 RANKL/OPG 比值及蝕骨細胞之分化標記 TRAP 基因表達均較卵巢切除之對照組小鼠為低。單獨餵食 isoflavone 之小鼠 RANKL/OPG 比值亦降低，且其 COX1、PGES1 表現量顯著增加，顯示植物性雌激素可增加 PGE2 的合成，抑制蝕骨細胞的骨質回收，減緩骨質的流失。綜合本實驗結果顯示 isoflavone 及 ozagrel 之補充能減緩停經所引起的骨質流失的發生。

關鍵字

骨質疏鬆症 ； 植物性雌激素 ； TXAS 抑制劑

並列摘要

Ghosal hematodiaphyseal dysplasia syndrome (GHDD) is a disorder with higher bone density. Genetic studies of patients with this disorder had identified mutations in the gene encoding thromboxane A2 synthase (TXAS), which is the key enzyme for producing thromboxane A2 (TXA2) in the metabolic cascade of arachidonic acid. Through modulating RANKL and osteoprotegerin (OPG) expression in primary cultured osteoblasts, TXA2 are involved in the maintenance of bone homeostasis. In osteoporotic women, the absence of estrogen loss its inhibition of IL-1β and IL-6 and these elevated interleukins stimulate the maturation of osteoclasts and induce osteoporosis. Thus, it was suggested that both TXA2 and estrogen play important roles in the maintenance of bone homeostasis. The main goal of this study is to evaluate the effect of phytoestrogen and TXAS inhibitors on the maintenance of bone mass. Five to six mice with ovariectomy (OVX) were randomly grouped into the followings: (1) control (OVX mice only); (2) isoflavone (OVX mice treated with soy isoflavone containing 35.51% genistein daily); (3) ozagrel (OVX mice treated with ozagrel, TXAS inhibitor, daily); (4) isoflavone and ozagrel (OVX mice treated with soy isoflavone and ozagrel daily). Our results demonstrate that the bone mineral density (BMD) of mice with sham-OVX was significantly higher than mice with OVX. After eight-week’s treatment, the BMD of OVX mice treated with isoflavone and ozagrel is significantly higher than OVX mice without any treatment. In order to further investigate the bone formation/absorption-related gene networks regulated by estrogen and TXA2, the expression of COX-1, PGES-1, TXAS, IL-1β, IL-6, TNF-α, OPG and RANKL were examined and RANKL/OPG ratio was calculated. Our results demonstrate that the supply of ozagrel may result in the decrease of bone loss, through down-regulating the expression of RANKL and RANKL/OPG ratio. In addition to lowering RANKL/OPG ratio, the supply of isoflavone may result in the decrease of bone loss, through up-regulating the expression of COX1 and PGES1, too. And the supply of both isoflavone and ozagrel may result in the decrease of bone loss, through down-regulating the expression of IL-6, RANKL, TRAP and RANKL/OPG ratio. Thus, it was concluded that the supply of isoflavone and ozagrel ameliorate the bone loss in mice with OVX.

並列關鍵字

TXAS inhibitor ； isoflavone ； osteoporosis

參考文獻

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