Mechanical testing
C M Langton, C F Njeh in The Physical Measurement of Bone, 2016
Anatomically, two forms of bone are distinguishable: the cortical (compact) and trabecular (spongy or cancellous) bone. Cortical bone appears as a solid continuous mass in which spaces can be seen only with the aid of a microscope. Cancellous bone on the other hand consists of a three-dimensional network of trabeculae, with the interspaces occupied by bone marrow. Both cortical and cancellous bones have a very similar basic composition, although the true density of fully calcified cancellous bone is a little lower (3%), and its proteoglycan content a little greater than those of the fully calcified compact bone. Although still contentious, the real difference between compact and cancellous bone depends on its porosity: that of compact bone, mainly due to the voids provided by osteon canals, Volkmann’s canals, osteocytes and their canaliculi and resorption lacunae, varies from 5 to 30% (apparent density about 1.8 g/cm3); the porosity of cancellous bone, chiefly due to the wide vascular and bone marrow intertrabecular spaces, ranges from 30 to more than 90% (apparent density 0.1 to 0.9 g/cm3) [2]. It has also been argued that since cancellous bone is more metabolically active compared with cortical bone, this could create newer and more mechanically competent bone [3]. Trabeculae are the unit components of the cancellous bone.
Nutraceuticals for Bone Health in Pregnancy
Priyanka Bhatt, Maryam Sadat Miraghajani, Sarvadaman Pathak, Yashwant Pathak in Nutraceuticals for Prenatal, Maternal and Offspring’s Nutritional Health, 2019
Bones are made of approximately 65% mineralized matrix grid (inorganic material), which mostly consists of crystallized hydroxyl apatite of bone tissue and is responsible for its rigid structure. The other 35% of bone is mostly fibrous protein, collagen (organic material). The collagen fibers are arranged throughout the bone tissue, which gives flexibility and strength. The bones’ inorganic and organic materials are organized into two distinct tissue types. There is spongy bone, called trabecular or cancellous bone, and compact bone called cortical bone (Figure 15.1). These two tissue types contrast in their microstructural design and porosity. Trabecular bone is 50% to 90% porous, making up around 20% of the adult skeleton, and it shows a lattice-like structure under the microscope. It is found at the ends of long bones, in the centers of vertebrae, and in the pelvis. The more dense cortical bone is about 10% porous and makes up about 80% of the adult skeleton. It looks like many concentric circles sandwiched together (Figure 15.2). Cortical bone tissue surrounds all trabecular tissue and is the main tissue in the shafts of long bones (Pandey et al. 2018).
Osteoporosis
Maria A. Fiatarone Singh, John Sutton Chair in Exercise, Nutrition, and the Older Woman, 2000
Bones are primarily made up of calcium, protein in the form of collagen fibers, and other minerals. There are two different types of bone tissue: trabecular bone and cortical bone. Approximately 80% of the skeleton is cortical bone, with the remaining 20% being made up of trabecular bone. All bones have both types of tissue; however, some bones are predominantly trabecular while others have greater amounts of cortical bone. Trabecular bone is lightweight and spongy in appearance because it is filled with red marrow and fat and is found in the vertebrae of the spine, the top part of the hips, the breast bone, and at the ends of the long bones in the arms and legs. Cortical bone, which is denser but thinner, surrounds trabecular bone and is found to a greater degree in the long bones of the arms and legs.
Heat shock protein 90 alpha and 14-3-3η in postmenopausal osteoporotic rats with varying levels of serum FSH
Published in Climacteric, 2020
Jianxia Huang, Jian Huang, Wensheng Hu, Zhifen Zhang
In this study, there were no significant differences in BMD across the treatment groups at the time of enrollment or after 4 weeks of treatment. This may because 4 weeks is not long enough for rats to develop the lowest BMD after ovariectomy. However, except for the sham group, BMD decreased most in the OVX + FSH group and decreased least in the OVX + LE group. These findings are consistent with Liu et al.’s previous report that, in ovariectomized rats, FSH can accelerate alveolar bone loss through FSHR independent of estrogen, and that LE, an FSH inhibitor, can protect alveolar bone loss in periodontitis23. Trabeculae play an important role in bone microstructure. The thickness, spacing, and number of trabeculae are closely related to bone strength24. With trabecular tissue damage, trabecular spaces become larger. In this study, H&E staining of the right femur was performed for rats in each group after 4 weeks. The results showed that bone trabecular area decreased gradually in the sham, OVX + LE, OVX, and FSH + OVX groups. The differences were statistically significant. Therefore, our study showed that increased serum FSH aggravated bone loss in a dose-dependent manner in postmenopausal osteoporotic rats.
Gut microbiota and metabonomics used to explore the mechanism of Qing’e Pills in alleviating osteoporosis
Published in Pharmaceutical Biology, 2022
Hui Xie, Zhengying Hua, Mengyu Guo, Shangyang Lin, Yaqian Zhou, Zebin Weng, Li Wu, Zhipeng Chen, Zisheng Xu, Weidong Li
Furthermore, QEP can affect special sequences of β collagen in blood markers, which are related to bone metabolism, such as β-cross laps, N-terminal osteocalcin and total procollagen type N-terminal propeptide. QEP also affects the mRNA expression of vitamin D receptors in OVX rats, thereby effectively controlling osteoporosis (Shuai et al. 2014). In this study, OVX rats exhibited remarkable osteoporotic changes in bone microstructure, including decreased BMD, BV/TV, BS/TV and Tb.N, and increased Tb.Sp. Decreased oestrogen levels in OVX rats lead to significant alteration of the microstructure of cancellous bones, which is characterized by the conversion of plate-like trabeculae to rod-like structures. This can increase trabecular separation and reduce the number of trabecular bones. Treatment with QEP can significantly alleviate these alterations in the bone microstructure of OVX rats. The results of this study demonstrate that QEP can inhibit the development of osteoporosis in OVX rats.
Concurrent consideration of cortical and cancellous bone within continuum bone remodelling
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Ina Schmidt, Areti Papastavrou, Paul Steinmann
Tubular bone is characterised by cortical bone surrounding the bone marrow in the shaft and the cancellous bone at the proximal and distal ends. Due to its special microstructure composed of beams and plates (trabeculae), cancellous bone is also denoted as spongy bone. Depending on environmental changes, such as mechanical loading, bone can adapt its internal microstructure by altering the density and trabecular orientation. Remodelling of cancellous bone was first formulated by Wolff (1892) and is referred to as Wolff’s law of bone remodelling. Based on continuum mechanics and the finite element method, simulation approaches to bone remodelling were developed, see Cowin and Hegedus (1976), Huiskes et al. (1987), Weinans et al. (1992), Harrigan and Hamilton (1993), Jacobs et al. (1995) and many more. Most of these studies address exclusively the adaptation of cancellous bone. Even if the focus is also on the adaptation of cortical bone, it is typically considered separately from spongy bone, see Carter and Beauprè (2010). One of the few approaches involving the interaction of both bone types was investigated by Hambli (2014) and Barkaoui et al. (2019) based on the cellular activities of bone. Another proposal was developed by Nutu (2018) based on the model of Huiskes et al. (1987) for dental implants.