Microvascular adaptation to growth in rat humeral head

Abstract

The aim of this work is to investigate the growth of the vasculature in the rat humeral head cartilage after the initial development of the secondary ossification centre until the adult organization. Rats aging from 5 weeks to 12 months were used. Histological observations on humeral heads were implemented with morphometrical analysis. Subsequently, vascular corrosion cast, that permits a three-dimensional observation of the vasculature, were prepared and observed by scanning electron microscopy. In young animals the epiphysis contains thin bone trabeculae and most of the epiphysis is occupied by bone marrow spaces. With age, the bone trabeculae progressively enlarge up to double their thickness. The percentage of bone tissue increases from 33.6 to 58.6% of the entire epiphysis, while the bone marrow spaces tend to increase very little in their mean dimension. Vascular corrosion casts show that the epiphyseal microcirculation is well distinguished from that of the diaphysis, and arises from the vessels present in the capsule and the periosteal networks. In young animals the only capillaries are bone marrow sinusoids and few subchondral capillaries. In adult animals small vessels run between the clusters of sinusoids forming the trabecular circulation. Capillary sprouts from sinusoids are always observed both in the young and adult animals. Thus, in adult rats different proper microcirculatory districts can be distinguished in the epiphysis: (a) the sinusoidal network, that supplies the hematopoiesis of the bone marrow and the adjacent osteogenic tissue; (b) the bone tissue microcirculation, limited to small vessels that supply the metabolism and the remodelling of the bone tissue. The reported microvascular organization and its adaptation to the epiphyseal growth represent the morphological basis for understanding the reciprocal interaction among the different tissues in developing and adult rat epiphysis.

Hypertension meets osteoarthritis — revisiting the vascular aetiology hypothesis

“…Subchondral bone comprises a subchondral trabecular meshwork and a cortical bone plate, which is separated from the calcified cartilage by the cement line. Trabecular bone of the epiphysis is highly vascularized, containing capillaries and a sinusoidal network 50,51 . In the hematopoietic bone marrow of the femoral head, microvessels are sinusoidal in form, whereas in the adipose bone marrow the microvessels are similar to capillaries in other tissues 50 .…”

The Effects of Hemodynamic Force on Embryonic Development

“…Finally, because flowing blood exerts drag on the vessel wall, the endothelial cells that line the vessel experience a frictional force known as shear stress (d). These hemodynamic forces are important at a variety of developmental time points and in a diverse range of vessel architectures, including those seen in: the heart (e – adapted with permission from Oxford University Press: figure 6a in reference [45]); the extraembryonic yolk sac (f); the bone (g – adapted with kind permission from Springer Science+Business Media : figure 8 in reference [82]); the placenta (h – © Society for Reproduction and Fertility (2009). Reproduced by permission.…”

Simultaneous 3D visualization and quantification of murine bone and bone vasculature using micro‐computed tomography and vascular replica

“…The surrounding tissue and bone is then removed (corroded) and the resulting replica is dried, rendered conductive, and examined using SEM (Hodde and Nowell, 1980;Northover et al, 1980). In particular, VCC combined with SEM was applied for the study of the vasculature and the microvasculature of bones primarily in rats (Aharinejad et al, 1995;Hirano et al, 1996;Morini et al, 1999Morini et al, , 2006Okada et al, 2002;Pannarale et al, 1997;Stanka et al, 1991). While vascular corrosion casts represent the 3D architecture of the vascular network, SEM can only provide two-dimensional (2D) data.…”