Osteocyte shape and mechanical loading

Abstract

There is considerable variation in the shape of osteocyte lacunae, which is likely to influence the function of osteocytes as the professional mechanosensors of bone. In this review, we first discussed how mechanical loading could affect the shape of osteocyte lacunae. Recent studies show that osteocyte lacunae are aligned to collagen. Since collagen fiber orientation is affected by loading mode, this alignment may help to understand how mechanical loading shapes the osteocyte lacuna. Secondly, we discussed how the shape of osteocytes could influence their mechanosensation. In vitro, round osteocytes are more mechanosensitive than flat osteocytes. Altered lacunar morphology has been associated with bone pathology. It is important to know whether osteocyte shape is part of the etiology.

Fig. 1

Polarized light microscopy of an osteon in a longitudinal section of cow femur. Bright areas indicate that collagen runs parallel to the plane of section. Note that osteocyte lacunae appear longer in the bright areas near the Haversian canal (hc) compared to the dark outer areas of the osteon. Scale bar = 50 μm

Fig. 2

Hypothetical explanation of observed differences in preferential collagen fiber orientation with loading mode (tension or compression)