Perinatal development of the rat hip joint with restrained fetal movement

Abstract

We compared the structures of the femoral head (FH) of neonates between normal and operated legs with restrained fetal movement using an exo utero technique. At embryonic day (E) 16.5, one hind limb was sutured onto the embryonic membrane and the fetuses were allowed to develop exo utero until the term (E22.5). There was no significant difference in the largest diameter of the FH between the non-operated and operated side FH in the operated neonates and the FH of the non-operated neonates. By scanning electron microscopy, roughness and collagen fiber bundles, which were detected on the surface of the operated side FH at E18.5, disappeared at E22.5. However, the operated side FH was deformed and the surface cell arrangement was more irregular than that of the controls at E22.5 by light microscopy. These results suggest that the abnormality of cell arrangement caused by the restraint of fetal movement may induce the deformity and irregularity of the FH surface, although this operation may not disturb the basic cellular activities such as cell proliferation as well as the secretion of cartilage ma-trix and collagen fibers. To further investigate the recovery process in the operated newborns after releasing the restraint, we bred them artificially for a considerable period after birth. The operated side FH surface of the neonate bred for 45 hours was smoother than that at E22.5 and similar to that of the non-operated side FH. This result suggests that the proper movement of the extremities after birth may recover the deformity caused by restrained fetal joint movement.

Regulation of immature cartilage growth by IGF-I, TGF-β1, BMP-7, and PDGF-AB: role of metabolic balance between fixed charge and collagen network

“…To estimate the rate of cartilage growth in vivo, measurements of the radius of the femoral condyle of a bovine fetus at a gestational age of 207 days [based on femur and tibia length and an overall gestational duration of 282 days (Pal et al 1981)] (11 mm), and of a 2 week old bovine calf (16 mm) were used. Growth rate in terms of radial growth (proportional to radius) and volumetric growth (proportional to radius cubed) was calculated as ∼54 µm/day and ∼2.2%/day, respectively, and is comparable to the radial growth of articular cartilage of the femoral head in neonatal rat (∼47 µm/day) (Hashimoto et al 2002), and the volumetric growth of cartilage from the femoral condyle in immature marsupial Monodelphis domestica (∼0.18%/day) (Hayes et al 2001). In contrast, growth rate during culture supplemented with serum or IGF-I was ∼2.7%/day or ∼180 µm/day in terms of thickness (calculated based on the rate of change in thickness of the S layer (31 µm/day, Fig.…”

Application of the mouse exo utero development system in the study of developmental biology and teratology

“…Although the gross morphologies of the femoral head and the hip joint cavity on the operated side at E18.5 were not different from those on the control side, histological changes were revealed in the operated side showing that: (i) the surface of the femoral head was rough with banked planes, and that surface collagen fibers did not form bundles; (ii) the cell shape and arrangement at the surface and in the underlying mesenchyme of the femoral head and the acetabulun became irregular; and (iii) collagen fibrils in intercellular spaces of the femoral head were dense but did not form bundles. Abnormal cell arrangement and irregularity of the surface of the femoral head were also observed in the operated side at term (E22.5) (Hashimoto et al . 2002).…”

“…2). Thus, the exo utero development system is also utilized to examine the effects of prenatal treatment on postnatal development (Hashimoto et al . 2002).…”

Articular cartilage tensile integrity: Modulation by matrix depletion is maturation-dependent

“…During prenatal or early postnatal growth periods, expansion of articular cartilage tissue occurs to accommodate the rapidly increasing size of the underlying bones and to meet the loading demands ex utero [43,44]. At skeletal maturity, after cessation of growth, articular cartilage homeostasis in terms of geometry, as well as composition, and function is desirable.…”