Influence of Prednisolone and Alendronate on the de novo Mineralization of Zebrafish Caudal Fin

Abstract

Dysregulated balance between bone resorption and formation mediates the onset and progression of osteoporosis. The administration of prednisolone is known to induce osteoporosis, whereas alendronate is commonly used to reverse the process. However, the assessment of the effects of such medicines on the nanostructure of bone remodeling and mechanical properties remains a major technical challenge. The aim of this study was to apply various analytical approaches to evaluate the compositional, morphological, and mechanical properties of regenerative zebrafish caudal fin bony rays affected by prednisolone and alendronate. Adult wild‐type AB strain zebrafish were first exposed to 125μM of prednisolone for 14 days to develop glucocorticoid‐induced osteoporosis. Fish fins were then amputated and let to regenerate for 21 days in tank water containing 30μM of alendronate or no alendronate. The lepidotrichia in the proximal and distal regions were evaluated separately using confocal microscope, scanning electron microscope, electron‐dispersive spectroscopy, Raman spectroscopy, atomic force microscopy, and a triboindenter. As expected, prednisolone led to significant osteoporotic phenotypes. A decrease of Ca/P ratio was observed in the osteoporotic subjects (1.46 ± 0.04) as compared to the controls (1.74 ± 0.10). Subsequent treatment of alendronate overmineralized the bony rays during regeneration. Enhanced phosphate deposition was detected in the proximal part with alendronate treatment. Moreover, prednisolone attenuated the reduced elastic modulus and hardness levels (5.60 ± 5.04 GPa and 0.12 ± 0.17 GPa, respectively), whereas alendronate recovered them to the pre‐amputation condition (8.68 ± 8.74 GPa and 0.34 ± 0.47 GPa, respectively). As an emerging model of osteoporosis, regrowth of zebrafish caudal fin was shown to be a reliable assay system to investigate the various effects of medicines in the de novo mineralization process. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Pharmacodynamic Material Basis and Potential Mechanism Study of Spatholobi Caulis in Reversing Osteoporosis

“…After removing MS-222 solution, 4% paraformaldehyde was utilized to fx zebrafsh and stained with 0.01% Alizarin Red Staining (ARS, containing 0.5% KOH) overnight [52]. After removal of ARS solution, newly prepared bleaching solution containing 1.5% H 2 O 2 and 0.5% KOH was added [53]. 1.5 hours later, all zebrafsh had been decolorized and preserved in diferent ratios of glycerol and 0.5% KOH solution [54].…”

Zebrafish models for glucocorticoid-induced osteoporosis

“…Continued prednisolone exposure could impair the expression of genes encoding extracellular matrix components and disrupt the machinery of macromolecule and vesicular transport[ 62 ]. A related study indicates that alendronate can restore the negative impact of glucocorticoids on caudal fin regeneration[ 63 ].…”

Fish Models of Induced Osteoporosis

“…Moreover, prednisolone altered the expression of several ECM related genes and continued exposure deteriorated cellular trafficking in the regenerating fin thus interfered with epithelial and bone tissue restoration upon amputation ( Schmidt et al, 2019 ). Again, alendronate was able to prevent prednisolone effects on fin ray mineralization and calcium/phosphorous levels, and restored bone biomechanical properties ( Bohns et al, 2020 ). There is, however, a striking difference between humans and zebrafish, when it comes to vertebrae, as adult zebrafish vertebrae are not affected by GC-induced bone loss.…”