Histological assessment for femora of ovariectomized obesity (db/db) mice carrying mutated leptin receptor

• Yusuke Tanaka ^[1] ; Tomoka Hasegawa ^[1] ; Tamaki Yamada ^[1] ; Tomomaya Yamamoto ^[1] ; Muneteru Sasaki ^[1] ; Hiromi Hongo ^[1] ; Kanako Tsuboi ^[1] ; Mai Haraguchi ^[1] ; Paulo Henrique Luiz de Freitas ^[2] ; Minqi Li ^[3] ; Kimimitsu Oda ^[4] ; Yasunori Totsuka ^[1] ; Kanchu Tei ^[1] ; Norio Amizuka ^[1]
  1. [1] Hokkaido University

     Hokkaido University

     Chūō-ku, Japón

     
  2. [2] Universidade Federal de Sergipe

     Universidade Federal de Sergipe

     Brasil

     
  3. [3] Shandong University

     Shandong University

     China

     
  4. [4] Niigata University

     Niigata University

     Nishi Ku, Japón

     

  Mostrar afiliaciones +
• Localización: Histology and histopathology: cellular and molecular biology, ISSN-e 1699-5848, ISSN 0213-3911, Vol. 31, Nº. 12, 2016, págs. 1315-1326
• Idioma: inglés
• Enlaces
  • Texto completo
• Resumen

  • In order to provide a clue to understand 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) on 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 a reduced number and thickness of metaphyseal trabeculae and 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 many adipocytes close to the metaphyseal chondro-osseous junction, while osteoblasts accumulated glycogen granules and lipid droplets. Therefore, it seems likely that the disruption of leptin signaling in db/db mice shifts the cell differentiation cascade towards the adipocyte lineage, resulting in an osteoporotic bone independently of estrogen deficiency