Journal: Bioactive materials

Article Title: A novel approach for the prevention of ionizing radiation-induced bone loss using a designer multifunctional cerium oxide nanozyme.

doi: 10.1016/j.bioactmat.2022.09.011

Figure Lengend Snippet: Fig. 5. Analysis of the radioprotective effect of CeONP60/40 (4 mg/kg) following exposure to levels of radiation able to induce bone loss in vivo. [A] Flow chart of the animal experiment. [B] Representative confocal micrographs of DNA damage (Comet Assay®) in bone marrow cells following exposure of the hind limbs to three fractions of 8 Gy (total 24 Gy) on days 1, 3 and 5 (n = 6). Quantification of tail length and comet length. Scale bar denotes 250 μm (left panel) and 50 μm (right panel). [C] Represen tative images of RANKL immunohistochemical stain ing (red arrows) in each of the experimental groups. Scale bar denotes 125 μm. [D] Multinucleated and active osteoclasts were identified via TRAP staining. Red arrows indicate TRAP + cells. The number of osteoclasts per unit of bone surface (cells/mm) were quantified by bone histomorphometric analyses (2 images/rat, n = 6). Scale bar denotes 250 μm. [E] Serum levels of CTX-1 in healthy control animals, X- Ray only, and X-Ray + CeONP60/40. ELISA results showed that CTX-1 concentrations were significantly reduced in rats following 4 mg/kg CeONP60/40 treat ment. All values are given as the mean ± SD. ****p < 0.0001. [F] Representative micrographs of SA-β-gal staining for senescent cells (stained blue). Scale bar denotes 500 μm. [G] Representative images of H&E staining. Note the extensive osteopenia at 14 days post-irradiation in the X-ray group. Scale bar denotes 500 μm. [H] Quantification of trabecular bone area (BA) to total area (TA). *p < 0.05, **p < 0.01. [I] A 3- point bending test was carried out and each tibia loaded to failure at a displacement rate of 0.02 mm/s. Ultimate stress and fracture stress in the control, X- Ray, and X-Ray + CeONP groups are presented (n = 6). The tibial parameters measured to obtain stress values are presented in Supplementary Table S1. All values are given as the mean ± SD. **p < 0.01, ***p < 0.001. [J] Representative 3D reconstruction images of the proximal tibia via nano-Ct scanning.

Article Snippet: To further investigate the effect of CeONP60/40 on bone resorption, bone resorption marker C-terminal end of the telopeptide of type I collagen (CTX-1) was measured in rat sera by ELISA (NBP2-69077, Novus Biologicals, USA) per manufacturer instructions.

Techniques: In Vivo, Single Cell Gel Electrophoresis, Immunohistochemical staining, Staining, Control, Enzyme-linked Immunosorbent Assay, Irradiation