Relationships between fetal body weight of Wistar rats at term and the extent of skeletal ossification

Abstract

We investigated the relationship between fetal body weight at term (pregnancy day 21) and the extent of ossification of sternum, metacarpus, metatarsus, phalanges (proximal, medial and distal) of fore-and hindlimbs and cervical and coccygeal vertebrae in Wistar rats. The relationships between fetal body weight and sex, intrauterine position, uterine horn, horn size, and litter size were determined using historical control data (7594 fetuses; 769 litters) of untreated rats. Relationships between body weight and degree of ossification were examined in a subset of 1484 historical control fetuses (154 litters) which were subsequently cleared and stained with alizarin red S. Fetal weight was independent of horn size, uterine horn side (left or right) or intrauterine position. Males were heavier than females and fetal weight decreased with increasing litter size. Evaluation of the skeleton showed that ossification of sternum, metacarpus and metatarsus was extensively complete and independent of fetal weight on pregnancy day 21. In contrast, the extent of ossification of fore-and hindlimb phalanges and of cervical and sacrococcygeal vertebrae was dependent on fetal body weight. The strongest correlation between body weight and degree of ossification was found for hindlimb, medial and proximal phalanges. Our data therefore suggest that, in full-term rat fetuses (day 21), reduced ossification of sternum, metacarpus and metatarsus results from a localized impairment of bone calcification (i.e., a malformation or variation) rather than from general growth retardation and that ossification of hindlimb (medial and proximal) phalanges is a good indicator of treatment-induced fetal growth retardation. Correspondence

Cyclooxygenase Inhibitors Affect Bone Mineralization in Rat Fetuses

“…However, similarly to the previous animal [Chahoud and Paumgartten, 2005] and human observations [Reid, 2002], a positive correlation between fetal growth parameters (i.e., weight, length and BMI) and bone mineralization was found. On the other hand, since growth retardation and decreased bone mineralization were observed more often in litters exposed to high toxic doses, the earlier reported maternal toxicity should be stressed as one of the mechanisms leading to disturbances in fetal bone physiology.…”

“…In the present study, reduced alizarin stain ing -a qualitative marker of bone mineralization -was revealed frequently in bones that undergo calcification at the end of the fetal period, e.g. phalanges, sternebra, cranial, metacarpal and metatarsal bones [Aliverti et al, 1979;Chahoud and Paumgartten, 2005]. As it was stressed before [Burdan, 2004[Burdan, , 2005, lack of mineralization in well-formed cartilages of metacarpal, metatarsal and hyoid bones in presently examined fetuses indicates 1-to 2-day retardation of the skeletal age [Aliverti et al, 1979].…”

Delayed ossification in Wistar rats induced by Morinda citrifolia L. exposure during pregnancy

“…After the fetuses had been cleared with KOH and the bones stained with alizarin red, skeletal alterations (skull, vertebral column, ribs, forelimbs, hindlimbs, sternum), sings of delayed ossification and variations were evaluated without the knowledge of the evaluator according to Atlas of external and skeletal anomalies in rats (Chahoud and Faqi, 1997).…”

Effect of Early Postnatal Body Weight on Femoral Head Ossification Onset and Hip Osteoarthritis in a Canine Model of Developmental Dysplasia of the Hip

“…There is little research addressing the relationship between birth weight and the extent of skeletal ossification. In late term pregnancy for rats (day 21), the extent of ossification in skeletal structures where ossification is beginning or still in progress is positively related to fetal weight (29). If this result in rats represents a general phenomenon of mammalian prenatal development, then the lower birth weight pups in the present study can be expected to have proportionately less ossification of the acetabulum and proximal femur at birth.…”