β-Hydroxy-β-Methylbutyrate (HMB) Supplementation Prevents Bone Loss during Pregnancy—Novel Evidence from a Spiny Mouse (Acomys cahirinus) Model

Abstract

The aim of this study was to determine the effects of ß-hydroxy-ß-methylbutyrate (HMB) supplementation during pregnancy on postpartum bone tissue quality by assessing changes in trabecular and compact bone as well as in hyaline and epiphyseal cartilage. The experiment was carried out on adult 6-month-old female spiny mice (Acomys cahirinus) divided into three groups: pregnant control (PregCont), pregnant HMB-treated (supplemented with 0.02 g/kg b.w of HMB during the second trimester of pregnancy, PregHMB), and non-pregnant females (NonPreg). Cross-sectional area and cortical index of the femoral mid-shaft, stiffness, and Young modulus were significantly greater in the PregHMB group. Whole-bone mineral density was similar in all groups, and HMB supplementation increased trabecular number. Growth plate cartilage was the thinnest, while the articular cartilage was the thickest in the PregHMB group. HMB supplementation increased the content of proteoglycans in the articular cartilage and the percentage of immature collagen content in metaphyseal trabeculae and compact bone. In summary, dietary HMB supplementation during the second trimester of pregnancy intensifies bone metabolic processes and prevents bone loss during pregnancy.

Femoral µCT Analysis, Mechanical Testing and Immunolocalization of Bone Proteins in β-Hydroxy β-Methylbutyrate (HMB) Supplemented Spiny Mouse in a Model of Pregnancy and Lactation-Associated Osteoporosis

“…TIMP-2 is responsible for the stimulation of osteoclastic bone resorption, and it is also associated with bone matrix mineralization [72,73]. In the case of HMB-induced dams, the increase of the OPG immune reaction, which is associated with decreased BMP-2, the increase in the TIMP-2 reaction at delivery was not able to increase bone resorption, which was similar to what was observed in delivered dam controls in a previous study [27].…”

“…All the results from the current study are in agreement with a recent study, which shows that HMB supplementation intensifies bone and matrix turnover, which is proven by the analysis of the content of immature collagen. The previous study also shows that HMB enhances the content of proteoglycans in the articular cartilage in pregnant females [27]. Chondrocytes in articular cartilage produce not only type II collagen, but also proteoglycans, synthesized and released into the matrix by chondrocytes, and their concentration indicates their metabolic ability [75].…”

“…Grey-level 16-bit 3D images were reconstructed using DatosX 2.0 software (GE Sensing & Inspection Technologies GmbH, Wunstorf, Germany). For scan visualization and analysis, the following software was used: VG Studio Max (v. 2.0, Volume Graphics GmbH, Heidelberg, Germany), ImageJ (v. 1.53j, U.S. National Institutes of Health, Bethesda, MA, USA) and Avizo (v. 9, FEI, Hillsboro, Oregon, USA) [ 27 ]. The following regions of interest (ROI) were analyzed using BoneJ plugin for ImageJ software [ 46 ]: (i) transverse section of bone mid-diaphysis (measurements of bone cross-section diameters, cross-sectional area, cortical index and mean relative wall-thickness), and (ii) sagittal section of the middle part of lateral condyle (measurements of trabecular bone volume fraction, trabecular thickness and trabecular separation) [ 47 ].…”

“…The spiny mouse is also considered as a suitable rodent model due to its long gestation period (38–39 days) [ 24 , 25 , 26 ]. A previous study involving HMB supplementation in pregnant spiny mice, showed that the administration of HMB significantly improved skeletal metabolic processes [ 27 ]. The prevalence of PLO during pregnancy highlights the need for possible effective methods of prevention and treatment of skeletal system disorders.…”

“…Functional food or supplements affecting skeletal tissue remodeling and homeostasis can be useful for prevention before PLO. Based on previous results, HMB supplementation during pregnancy has been shown to have a positive effect, not only on the offspring, but also on the pregnant dam’s skeletal system [ 21 , 27 , 28 , 29 ]. Taking into account the influence of pregnancy on bone quality and the effect of HMB in protecting pregnant women against excessive bone loss, it seems reasonable to investigate the effects of HMB supplementation during pregnancy on the immunolocalization of selected proteins involved in bone metabolism in pregnancy and lactation.…”