Rapid improvements in cortical bone dynamics and structure after lactation in established breeder rats
- 24 January 2004
- journal article
- research article
- Published by Wiley in The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology
- Vol. 276A (2), 143-149
- https://doi.org/10.1002/ar.a.10138
Abstract
The mineral requirements for milk production during lactation usually result in a decrease in maternal skeletal mass during this period. The purpose of this study was to characterize changes in cortical bone formation, resorption, and structure after lactation in established breeder rats. Rats were taken at the end of the second pregnancy, second lactation, and at two, four, and six weeks after the pups were weaned. Age‐related, nulliparous groups were included for comparison. Cortical bone structure and bone formation and resorption were measured at the tibiofibular junction using histomorphometric methods. As expected, there were decreases in cortical bone area, width, and minimum cortical thickness with an increase in marrow cavity area during lactation. Bone formation rates were essentially zero on the periosteal and endocortical surfaces at the end of lactation, while eroded (resorption) endocortical surface was greatly increased compared with the end of pregnancy. At or immediately after weaning, there was a rapid reversal of resorption to formation surface on the endocortical envelope similar to the events of true bone remodeling. Likewise, there was a commencement of bone formation on the periosteal surface. The volume‐ and surface‐referent bone rates measured on the endocortical surface were substantially elevated over those measured at the end of the second pregnancy or in the nulliparous animals. Peak bone formation rates were observed on both the endocortical and periosteal surfaces by four weeks after weaning. These results show that the postlactation period is profoundly anabolic for cortical bone in the established breeder rat. The rapid and dramatic increases in bone formation likely serve to restore bone lost during lactation and to prepare the maternal skeleton for the next reproductive cycle. Anat Rec Part A 276A:143–149, 2004.Keywords
This publication has 52 references indexed in Scilit:
- Greatly Increased Cancellous Bone Formation With Rapid Improvements in Bone Structure in the Rat Maternal Skeleton After LactationJournal of Bone and Mineral Research, 2002
- Calcium in Pregnancy and LactationAnnual Review of Nutrition, 2000
- Skeletal mass, chemistry, and growth during and after multiple reproductive cycles in the ratBone, 1999
- Maternal-Fetal Calcium and Bone Metabolism During Pregnancy, Puerperium, and LactationEndocrine Reviews, 1997
- Skeletal structural adaptations to mechanical usage (SATMU): 2. Redefining Wolff's Law: The remodeling problemThe Anatomical Record, 1990
- Human lactation: Forearm trabecular bone loss, increased bone turnover, and renal conservation of calcium and inorganic phosphate with recovery of bone mass following weaningJournal of Bone and Mineral Research, 1990
- Increased cancellous bone remodeling during lactation in beaglesBone, 1989
- Bone histomorphometry: Standardization of nomenclature, symbols, and units: Report of the asbmr histomorphometry nomenclature committeeJournal of Bone and Mineral Research, 1987
- Changes in bone mineral and bone formation rates during pregnancy and lactation in ratsBone, 1986
- Studies of the skeleton of the sheep I. The effect of different levels of dietary calcium during pregnancy and lactation on individual bonesThe Journal of Agricultural Science, 1955