The effect of hydrochloric acid on microstructure of porcine (Sus scrofa domesticus) cortical bone tissue

Abstract

We evaluated the degradation of cortical bone tissue by hydrochloric acid (HCl) since intentional bone decalcification in a forensic context has not been studied on a histomorphological level. We used 70 pig metatarsal bones split into subsamples and immersed in one of three concentrations of acidic solutions (0.5M, 1M, 2M HCl) for two and four hours. We analyzed the cortical thicknesses on transversal cross-sections, thicknesses of the three histomorphologically distinct zones present in acid-immersed bones, and number and area of crystals present in one of the zones. Furthermore, we analyzed the ratio of calcium to phosphorus (Ca:P). We observed a division of the cortical bone cross section into three distinctive zones: demineralized matrix (DM) in the periosteal part of bone, middle contact zone (CZ), and mineralized matrix (MM) in the endosteal part of bone. With increasing acid concentration and time of immersion (from 0.5M HCl for 2h to 2M HCl for 4h), the thickness of DM increased by 67%, the thickness of CZ increased by 56%, and the thickness of MM decreased by 32%. The Ca:P ratio in the contact zone of acid-treated samples did not change significantly with changing acid concentration and time of immersion. The Ca:P ratio of the CZ decreased by 10% when compared to the Ca:P ratio of MM in acid-treated samples. Moreover, we observed crystals on the outer periosteal border of the DM zone, in the CZ, and in the MM Haversian/Volkmann's canals. The size and number of the crystals in the CZ of acid-treated bones increased with acid concentration and time of acid immersion. Moreover, we also observed significant differences in all analyzed properties between anatomical regions. Due to varying reactions to acid immersion among anatomical regions, bone micro-degradation should be observed separately for each region.

Інформативність Мікроскопічних Структур Діафіза Кісток Плесна Самок Великої Рогатої Худоби Для Судово- Ветеринарного Визначення Їхнього Віку

“…doi: 10.31210/visnyk2022.04. 23 Based on the analysis of the remains of the skeleton of the limbs, it is possible to establish the species and age of the animal, as well as the peculiarities of the functioning of the movement apparatus during the postnatal period of ontogenesis. Histological studies of bones, in particular the number of microstructures per unit area of the sample, are used to reconstruct the pre-mortem conditions in vertebrates.…”

“…Збільшення кількості вторинних остеонів (систем Гаверса) свідчить про ступінь мінералізації компактної кісткової тканини кісток плесна. Автори [23] встановили наявність як демінералізованого матриксу в окісті, так і мінералізованого -в ендостальній частині кістки.…”

X-ray diffraction studies of a partially demineralized oriented cortical bone with the controlled depth of analysis

“…In the process of dissolution of the cortical bone mineral the formation of a growing demineralized layer on the bone surface takes place, and the reaction front advances into the tissue with increasing immersion time of bone block in the decalcifying agent [ [13] , [14] , [15] ]. Moreover, while Lewandrowski et al [ 13 ] and Horneman et al [ 14 ], with some stipulations, reported on the two-zone structure (demineralized and mineralized matrix) of the transverse section of the bone after acid treatment, in Ref.…”

A comparison of three decalcification agents for assessments of cranial fracture histomorphology

“…Numerous studies have performed comparative analyses of histological preservation by decalcifying agents, with a general consensus that slow decalcifications in EDTA provides superior outcomes for staining and cell and tissue morphology at the cost of lengthy immersion times [1,4,7,[11][12][13]15,16]. However, these inquiries are predominately based on animal models [4,5,7,8,11,[16][17][18] and human dentition [9,13,15], rather than human cranial bone. Furthermore, exhaustive literature searches yielded no available standards for the decalcification of healing bone.…”