Morphology of aged turquoise killifish bone imaged with ZEISS Xradia Versa X-ray microscope

Skeletal Aging of the Turquoise Killifish with X-ray Microscopy: A New Model for Human Bone Disease

byZEISS Microscopy 27 November 2023 3 min read

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Skeletal Aging of the Turquoise Killifish Quantified with X-ray Microscopy

High-resolution X-ray microscopy imaging of turquoise killifish spines provides evidence of their use as a model for studying age-related bone diseases, such as spinal stenosis, in humans.

At the center of our body is the spine. As we age, our spines can degenerate, leading to conditions like spinal stenosis, which cause chronic pain and poor quality of life for older individuals.

Dr. Yumi Kim is a Research Assistant Professor at the Department of Biomedical Engineering, UNIST (Ulsan National Institute for Science and Technology), South Korea. The primary goal of her research is to elucidate methodologies for extending healthy lifespans. She employs the turquoise killifish, a species which has gained prominence in the field of aging research due to its abbreviated lifespan and its highly conserved aging phenotype with mammals, including humans.

In a recent publication, Dr. Kim’s team investigated whether the turquoise killifish can serve as a disease model for age-associated spinal stenosis, with the aim of using it as a tool for drug screening for this disease. In their work, they used the ZEISS Xradia Versa X-ray microscope for high-resolution tomographic imaging to study skeletal development and age-related changes.

Obtaining clear images of small fish bones is a crucial aspect of our research. The results from ZEISS Xradia Versa are not only scientifically informative but also visually excellent with beautiful images that showcase the delicate and complex nature of killifish skeletal systems.

Dr. Yumi Kim
Research Assistant Professor at the Department of Biomedical Engineering, UNIST, South Korea

Example of an aging turquoise killifish skeleton that has been imaged to investigate spine curvature and vertebral collapse between the precaudal and caudal vertebrae in the Weberian vertebrae. Imaged with the ZEISS Xradia Versa 620 X-ray microscope.

Non-destructive Imaging of Vertebrae with X-ray Microscopy

Aging and spawning cause structural deformations of the skeleton

In their publication, Dr. Kim and colleagues quantified age- and breeding-dependent body shape and spine structures to identify the skeletal alterations that occur during aging and breeding status in female turquoise killifish. One part of their work included the use of X-ray tomography with ZEISS Xradia Versa X-ray microscope to perform bone morphometric analyses. Additionally, high-resolution X-ray tomography analyses were performed on single caudal vertebra for a detailed examination of the cortical bone and tissues to examine vertebra architecture.

Example vertebral image of an aged turquoise killifish used for bone morphometric analyses. Imaged using the ZEISS Xradia Versa 620 X-ray microscope.

Bone Morphometric Analyses

High-resolution X-ray tomography images acquired using the ZEISS Xradia Versa X-ray microscope were used to determine bone morphometric analyses including bone volume (BV), bone volume fraction (BV/TV), and bone mineral density (BMD) in whole fish. This identified spinal curvature and vertebral collapse in specific regions of the spine. Subsequent measurements of the first caudal vertebrae (FCV) in aged and breeding fish were performed on images such as the one shown here to further investigate the specific area affected by age and spawning.

Three-dimensional image of the FCV (first caudal vertebrae) in an aged turquoise killifish. Cortical bones are depicted in yellow, and the tissue region of the FCV is shown in pink. Imaged with ZEISS Xradia Versa 620 X-ray microscope.

Investigating Vertebrae Architecture

To further investigate the specific area of the spine affected by age and spawning, the anatomy of the first caudal vertebrae (FCV) was examined through 3D reconstruction using the ZEISS Xradia Versa X-ray microscope. An example image is shown here. The cortical bone is shown in yellow and the tissues are shown in pink. Dr. Kim and her team used images such as these to identify anatomical differences between females who either had or had not spawned, with breeding severely reducing the intervertebral space.

Research team with pages from their publication in iScience — Top Right Inset: Research team, left to right, Jae-Il Park, Yumi Kim, Su-Hyeon Cho, and Kil-Nam Kim. Figures are from their article in *iScience*.

Turquoise Killifish as a Model for Human Bone Disease

In their publication, Dr. Kim and colleagues evaluated turquoise killifish as a potential model for studying age- and reproduction-associated spinal stenosis. X-ray tomography played an important role in revealing fish age- and breeding-dependent changes in BMD, bone volume, cortical bone thickness, and additional bone morphometric analyses as well as quantitative and anatomical first caudal vertebrae (FCV) analyses. Their additional experiments included quantitative analyses of body shape, mineralization studies using laser scanning confocal microscopy, and gene expression studies. They propose that turquoise killifish could be a powerful model for studies of human bone diseases, especially spinal stenosis, during natural aging.

Read their full article in iScience for all the details, including their bone morphometric calculations, on this fascinating work.