Changes in cortical bone channels network and osteocyte organization after the use of zoledronic acid

Objective The aim of this study was to evaluate the effects of zoledronic acid (ZA) on the cortical bone channels network (CBCN) and osteocyte organization in relation to the bone channels. Materials and methods Eighteen male Wistar rats were divided into control (CG) and test groups (TG). Twelve animals from TG received 3 ZA doses (7.5 µg/kg), and 6 animals from CG did not receive any medication. TG animals were euthanized at 14 (n = 6) and 75 (n = 6) dadys after drug injection. CBCN was analyzed in mandibles and tibias using computational routines. The osteocyte organization was qualitatively evaluated in tibias using a three-dimensional reconstruction of images from serial histological sections. Results Significant differences in CBCN of tibia were found between the treated and untreated rats, with a wider range of sizes and shapes of the channels after the use of ZA (channels area p = 0.0063, channels area SD p = 0.0276) and less bone matrix (bone volume p = 0.0388). The alterations in the channels’ morphology were more evident at 75 days after the drug injection (channels perimeter p = 0.0286). No differences were found in mandibles CBCN. The osteocyte distribution revealed more variable patterns of cell distribution in ZA groups, with non-homogeneous distribution of cells in relation to the bone channels. Conclusion Zoledronic acid induces structural changes in CBCN and modifies the osteocyte arrangement in cortical bone in the tibia; also, the variability in the morphology of bone channels became more evident after a certain time of the use of the drug.

Changes in cortical bone channels network and osteocyte organization after the use of zoledronic acid.

OBJECTIVE: The aim of this study was to evaluate the effects of zoledronic acid (ZA) on the cortical bone channels network (CBCN) and osteocyte organization in relation to the bone channels. MATERIALS AND METHODS: Eighteen male Wistar rats were divided into control (CG) and test groups (TG). Twelve animals from TG received 3 ZA doses (7.5 µg/kg), and 6 animals from CG did not receive any medication. TG animals were euthanized at 14 (n = 6) and 75 (n = 6) dadys after drug injection. CBCN was analyzed in mandibles and tibias using computational routines. The osteocyte organization was qualitatively evaluated in tibias using a three-dimensional reconstruction of images from serial histological sections. RESULTS: Significant differences in CBCN of tibia were found between the treated and untreated rats, with a wider range of sizes and shapes of the channels after the use of ZA (channels area p = 0.0063, channels area SD p = 0.0276) and less bone matrix (bone volume p = 0.0388). The alterations in the channels' morphology were more evident at 75 days after the drug injection (channels perimeter p = 0.0286). No differences were found in mandibles CBCN. The osteocyte distribution revealed more variable patterns of cell distribution in ZA groups, with non-homogeneous distribution of cells in relation to the bone channels. CONCLUSION: Zoledronic acid induces structural changes in CBCN and modifies the osteocyte arrangement in cortical bone in the tibia; also, the variability in the morphology of bone channels became more evident after a certain time of the use of the drug.

New formulas to estimate age at death in Maya populations using histomorphological changes in the fourth human rib*.

This study develops new histomorphological algorithms for Maya populations' human ribs and tests the applicability of published algorithms. Thin sections from the fourth rib of 36 individuals of known age were analyzed under polarized light microscopy. Osteon population density (OPD, the concentration of intact and fragmented osteons per mm(2)), cortical area (CA), and osteon size (OS) were recorded. Seven algorithms were calculated, using all combinations of variables, and compared to the performance of published formulas. The OPD-based formulas deviate from the known age 8.7 years on average, while those from OS and CA deviate between 10.7 and 12.8 years. In comparison, our OPD-based algorithms perform better than the one by Stout and Paine and much better than Cho et al. In conclusion, algorithms should be developed using OPD for different ethnic groups; although Stout and Paine's can be used for Maya and maybe Mesoamerican individuals.

Descripción histológica de la substancia cortical dorsal en la parte media de la diáfisis del metacarpiano III en yegua mestiza / Histological description of the dorsal cortical bone in the midle diaphysis of the metacarpial III in the mixed mare

El hueso es el unicó tejido capaz de adaptarse estructural y geométricamente ante presiones impuestas sobre él. Durante la vida, el hueso es afectado por procesos externos e internos. Los externos producen cambios en sus medidas y forma. Los internos remodelan su arquitectura interna. Además, los huesos son afectados por factores que incluyen edad, sexo, especie, origen y contenido de minerales. Las variaciones estructurales en la organización microscópica del tejido óseo ocurren de manera constante y consistente mediante el crecimiento y la remodelación por parte de cada especie animal. El objetivo del presente trabajo fue estudiar la estructura microscópica inorgánica del cuadrante dorsal del metacarpiano III en la parte media de la diáfisis en distintos grupos etarios. Se estudió la substancia cortical dorsal de los huesos metarcapianos III izquierdos provenientes de 30 yeguas mestizas, con edades entre 2 y 5 años. Extraídos los huesos se los liberó de los tejidos blandos. El cuadrante dorsal fue muestreado, en la parte media de la diáfisis. Posteriormente, se realizó el pulido en forma manual. Las muestras fueron observadas al microscopio de luz polarizada. Se observaron diferencias histológica en los diferentes grupos etarios. Se concluyó que se producen variaciones microscópicas de la subtancia cortical dorsal del metarcapiano III en la parte media de la diáfisis, en el transcurso de 4 años