Bone resorption and formation in the pedicles of European roe deer (Capreolus capreolus) in relation to the antler cycle—A morphological and microanalytical study

Abstract

We analyzed pedicle bone from roe bucks that had died around antler casting or shortly before or during the rutting period. Pedicles obtained around antler casting were highly porous and showed signs of intense osteoclastic activity that had caused the formation of an abscission line. Following the detachment of the antler plus a portion of pedicle bone, osteoclastic activity in the pedicles continued for some time, and new bone was deposited onto the separation plane of the pedicle stump, leading to partial pedicle restoration. Pedicles obtained around the rutting period were compact structures. The newly formed, often very large secondary osteons, which had filled the resorption cavities, exhibited a lower mineral density than the persisting older bone. The middle zones of the lamellar infilling frequently showed hypomineralized lamellae and enlarged osteocyte lacunae. This indicates a deficiency in mineral elements during the formation of these zones that occurred along with peak antler mineralization. We suggest that growing antlers and compacting pedicles compete for mineral elements, with the rapidly growing antlers being the more effective sinks. The competition between the two simultaneously mineralizing structures is probably more severe in Capreolus capreolus than in other cervids. This is because roe bucks regrow their antlers during late autumn and winter, a period of limited food and associated mineral supply. The pedicle is a heavily remodeled bone structure with distinct seasonal variation in porosity. Pedicle remodeling differs in several aspects from the normal bone remodeling process in the mammalian skeleton.

Zinc-alkaline phosphatase at sites of aortic calcification

“…High Zn concentrations are found in the matrix zones just before the onset of mineralization and at the mineralizing sites in epiphyseal cartilage (Doty et al 1981;Chichocki et al 1988;Vittur et al 1992;Silva Barreto et al 2020) and bone tissues (Doty et al 1981;Gomez et al 1999Gomez et al , 2006. In addition, accumulated Zn in the mineralized matrix has been reported as Zn lines and Zn stripes in calcified cartilage (Rizzo et al 1995;Zöger et al 2006;Bradley et al 2007;Kaabar et al 2010;Raoult et al 2018;Stock et al 2022;Kierdorf et al 2022), bone (Pemmer et al 2013;Kierdorf et al 2023), cementum (Martin et al 2004;Stock et al 2017;Dean et al 2018), dentin (Stock et al 2014;Dean et al 2023), and enamel (Dean et al 2019(Dean et al , 2023.…”

“…As a matter of speculation, it is possible to consider that the Zn lines found within the mineralized bone matrix, away from the ion exchange bone surfaces, could correspond to episodes of mineralization restart where high concentrations of TNAP were buried. Thus, TNAP may play a predominant role in de novo mineralization, since Zn is more concentrated in the cement lines of the bone remodeling units, in the so-called lines of arrested growth, and in the woven bone, which mineralizes very rapidly (Gomez et al 1999(Gomez et al , 2006Pemmer et al 2013;Kierdorf et al 2023). The absence of active TNAP has the opposite effect.…”