Virchows Archiv

, Volume 370, Issue 1, pp 55–68

The influence of immobilization on osteocyte morphology

Osteocyte differential count and electron microscopical studies
  • B. Krempien
  • Ch. Manegold
  • E. Ritz
  • J. Bommer
Article

DOI: 10.1007/BF00427310

Cite this article as:
Krempien, B., Manegold, C., Ritz, E. et al. Virchows Arch. A Path. Anat. and Histol. (1976) 370: 55. doi:10.1007/BF00427310

Summary

Differential counts and electron microscopical studies of osteocytes were performed on rats immobilized by spinal cord severing, plaster cast and ischiatic nerive dissection. In undecalcified ground sections of tibia and femur (100 micron) stained wtth basic fuchsin, osteocytes were differentiated into small (metabolically inactive) osteocy es enlarged (metabolically activated) osteocytes and empty lacunae. In rats (immobilizedfor' three weeks) with functioning parathyroid glands, but not after parathyroidectomy, the number of activated cells is markedly increased, whereas the number of small osteocytes is reduced. In animals with spinal cord severing the number of empty lacunae is also increased.

Electron microscopical studies of undecalcified tibiae taken from rats immobilized for ten days showed a periosteocytic osteolysis with destruction of the lacunar wall, fragmentation of collagen fibres and loss of mineral crystals. The cytoplasmic seams of osteocytes were broadened, mitochondria were enlarged, and the cytoplasma showed vacuoles containing amorphous material which could be found in the pericellular space. Deep invaginations of the cytoplasma and an increase of the cell processes were typical findings.

The results of the investigation point to an activation of osteocyte metabolism by immobilization. The osteocytes thus play an important part at the onset of immobilization osteoporosis. Periosteocytic osteolysis can be inhibited by parathyroidectomy. Therefore, the response of osteocytes to endogenous parathyroid hormone must be altered under conditions of immobilization.

Copyright information

© Springer-Verlag 1976

Authors and Affiliations

  • B. Krempien
    • 1
  • Ch. Manegold
    • 1
  • E. Ritz
    • 1
  • J. Bommer
    • 1
  1. 1.Department of Pathology and Department of Internal MedicineUniversity of HeidelbergFederal Republic of Germany

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