並列タイトル等卵巣摘出を施したレプチン受容体変異肥満(db/db)マウスの大腿骨における組織学的解析
一般注記In order to provide a clue for understanding of the interplay between leptin and estrogen, we have examined femoral metaphyses of ovariectomized db/db mice carrying a mutated leptin receptor. We performed ovariectomy (OVX) or sham-operation (sham) to 12-week old female wild-type and db/db mice, and then, after 8 weeks, divided the animals into four groups: wild-type sham, wild-type OVX, db/db sham and db/db OVX. Samples from all groups were prepared for histochemical and ultrastructural examinations. As a result, db/db sham mice showed the reduced number and thickness of metaphyseal trabeculae and an excessive adipose tissue when compared to wild-type sham mice. The wild-type OVX group exhibited markedly-diminished trabecular number, as well as lower populations of osteoblasts and osteoclasts in comparison to wild-type sham group. On the other hand, trabecular numbers were similar for the two db/db groups, suggesting that the effect of the ovariectomy,i.e., estrogen deficiency may be lessened in this animal model. Leptin receptor was mainly found in osteoblasts and in bone marrow stromal cells including adipocytes. In addition, the expression of estrogen receptor did not seem to change after OVX in wild-type mice and in db/db mice. Both db/db sham and OVX mice featured a thick adipocyte layer close to the metaphyseal chondo-osseous junction, while osteoblasts accumulated glycogen granules and lipid droplets. Therefore, it seems likely that the disruption of leptin signalingin db/db mice shifts the cell differentiation cascade towards the adipocyte lineage, resulting in an osteoporotic bone independently of estrogen deficiency.
(主査) 教授 鄭 漢忠, 教授 網塚 憲生, 教授 土門 卓文
歯学研究科(口腔医学専攻)
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受理日(W3CDTF)2015-02-03T05:25:05+09:00
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