The early mouse 3D osteocyte network in the presence and absence of mechanical loading

Yasuyo Sugawara, Hiroshi Kamioka, Yoshihito Ishihara, Naoko Fujisawa, Noriaki Kawanabe, Takashi Yamashiro

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Osteocytes are considered to act as mechanosensory cells in bone. They form a functional synctia in which their processes become interconnected to constitute a three-dimensional (3D) network. Previous studies reported that in mice, the two-dimensional osteocyte network becomes progressively more regular as they grow, although the key factors governing the arrangement of the osteocyte network during bone growth remain unknown. In this study, we characterized the 3D formation of the osteocyte network during bone growth.Morphological skeletal changes have been reported to occur in response to mechanical loading and unloading. In order to evaluate the effect of mechanical unloading on osteocyte network formation, we subjected newborn mice to sciatic neurectomy in order to immobilize their left hind limb as an unloading model. The osteocyte network was visualized by staining osteocyte cell bodies and processes with fluorescently labeled phalloidin. First, we compared the osteocyte network in the femora of embryonic and 6-week-old mice in order to understand the morphological changes that occur with normal growth and mechanical loading. In embryonic mice, the osteocyte network in the femur cortical bone displayed a random cell body distribution, non-directional orientation of cell processes, and irregularly shaped cells. In 6-week-old mice, the 3D network contained spindle-shaped osteocytes, which were arranged parallel to the longitudinal axis of the femur. In addition, more and longer cell processes radiated from each osteocyte. Second, we compared the cortical osteocyte networks of 6-week-old mice that had or had not undergone sciatic neurectomy in order to evaluate the effect of unloading on osteocyte network formation. The osteocyte network formation in both cortical bone and cancellous bone was affected by mechanical loading. However, there were differences in the extent of network formation between cortical bone and cancellous bone in response to mechanical loading with regard to the orientation, nuclear shape and branch formation.

Original languageEnglish
Pages (from-to)189-196
Number of pages8
JournalBone
Volume52
Issue number1
DOIs
Publication statusPublished - Jan 2013

Fingerprint

Osteocytes
Femur
Bone Development
Bone and Bones
Phalloidine

Keywords

  • Mechanical loading
  • Network formation
  • Osteocytes
  • Three-dimensional morphology

ASJC Scopus subject areas

  • Physiology
  • Endocrinology, Diabetes and Metabolism
  • Histology

Cite this

The early mouse 3D osteocyte network in the presence and absence of mechanical loading. / Sugawara, Yasuyo; Kamioka, Hiroshi; Ishihara, Yoshihito; Fujisawa, Naoko; Kawanabe, Noriaki; Yamashiro, Takashi.

In: Bone, Vol. 52, No. 1, 01.2013, p. 189-196.

Research output: Contribution to journalArticle

Sugawara, Yasuyo ; Kamioka, Hiroshi ; Ishihara, Yoshihito ; Fujisawa, Naoko ; Kawanabe, Noriaki ; Yamashiro, Takashi. / The early mouse 3D osteocyte network in the presence and absence of mechanical loading. In: Bone. 2013 ; Vol. 52, No. 1. pp. 189-196.
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