caa a22 4500 605520844 CHVBK 20210128100737.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s00223-015-0035-0 doi (NATIONALLICENCE)springer-10.1007/s00223-015-0035-0 Vertical Trabeculae are Thinned More Than Horizontal Trabeculae in Skeletal-Unloaded Rats [Elektronische Daten] [Jens Vegger, Annemarie Brüel, Jesper Thomsen] Skeletal unloading results in a rapid thinning of the trabecular bone network, but it is unknown whether vertical and horizontal trabeculae are equally affected. Therefore, the purpose of the present study was to investigate whether horizontal and vertical trabeculae were thinned similarly during skeletal unloading in rats. Fifty-seven 16-week-old female Wistar rats were randomized into six groups: baseline; control 4weeks; botulinum toxin A (BTX) 4weeks; control 8weeks; BTX 8weeks; and two BTX injections 8weeks (BTX+BTX8). The BTX animals were injected in the right hind limb with 4IU BTX at the start of the study, while the BTX+BTX8 were also injected with 2IU BTX after 4weeks. The animals were killed after 0, 4, or 8weeks. The distal femoral metaphyses were μCT scanned, and the strengths of the femoral necks, mid-diaphyses, and distal femoral metaphyses were ascertained. Disuse resulted in a significant loss of BV/TV, thinning of the trabeculae, and decrease in the degree of anisotropy, and in a significant reduced bone strength after both 4 and 8weeks. The ratio of horizontal to vertical trabecular thickness (Tb.Th.horz/Tb.Th.vert) and the ratio of horizontal to vertical bone volume (BV.horz/BV.vert) were significantly higher in BTX animals than in control animals. In addition, the horizontal and vertical trabecular thickness probability density functions were more similar in BTX animals than in control animals. In conclusion, skeletal unloading decreased BV/TV, Tb.Th, the degree of anisotropy, and mechanical strength, while BV.horz/BV.vert and Tb.Th.horz/Tb.Th.vert were increased. This indicates that the more loaded vertical trabeculae are pronouncedly more thinned than the less loaded supporting horizontal trabeculae during unloading. Springer Science+Business Media New York, 2015 Bone microstructure nationallicence MicroCT nationallicence Histomorphometry nationallicence Skeletal unloading nationallicence Rat nationallicence Vegger Jens Department of Biomedicine - Anatomy, Aarhus University, Wilhelm Meyers Allé 3, 8000, Aarhus C, Denmark aut Brüel Annemarie Department of Biomedicine - Anatomy, Aarhus University, Wilhelm Meyers Allé 3, 8000, Aarhus C, Denmark aut Thomsen Jesper Department of Biomedicine - Anatomy, Aarhus University, Wilhelm Meyers Allé 3, 8000, Aarhus C, Denmark aut Calcified Tissue International Springer US; http://www.springer-ny.com 97/5(2015-11-01), 516-526 0171-967X 97:5<516 2015 97 223 https://doi.org/10.1007/s00223-015-0035-0 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00223-015-0035-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Vegger Jens Department of Biomedicine - Anatomy, Aarhus University, Wilhelm Meyers Allé 3, 8000, Aarhus C, Denmark aut NATIONALLICENCE 700 1- Brüel Annemarie Department of Biomedicine - Anatomy, Aarhus University, Wilhelm Meyers Allé 3, 8000, Aarhus C, Denmark aut NATIONALLICENCE 700 1- Thomsen Jesper Department of Biomedicine - Anatomy, Aarhus University, Wilhelm Meyers Allé 3, 8000, Aarhus C, Denmark aut NATIONALLICENCE 773 0- Calcified Tissue International Springer US; http://www.springer-ny.com 97/5(2015-11-01), 516-526 0171-967X 97:5<516 2015 97 223