This final technical report discusses a research project that aimed to develop a longitudinal model for studying the effects of prolonged opioid exposure on cortical bone remodeling in rabbits.
The authors of this technical report describe a research study aimed at developing a longitudinal model for studying the effects of prolonged drug exposure, specifically opioids, on cortical bone remodeling in an animal that was selected for having similar cortical bone remodeling to that of humans. The ultimate goal was to describe how analgesic drugs, specifically morphine and fentanyl, affect microscopic structures of cortical bone used in histological age estimation methods in forensic anthropology; the researchers also hope to improve the applicability of histological age-estimation methods and improve scientific standards within the field of forensic anthropology. Within the stated goals, the authors’ three objectives were: to characterize cortical bone microstructural changes in a rabbit opioid model; to optimize 3D micro-CT (Computed Tomography) imaging of remodeling events in an opioid rabbit model; and determine if prolonged opioid use is discernable in cortical bone microstructural features used in histological age-at-death estimation. The authors report complications with the experimental dosing period, noting difficulties with preventing the rabbits from removing their experimental manipulations; they describe the tailored operating protocol that they developed to resolve the issues. Outcomes include the development of specific standard operating procedures and image processing workflows for the 3D imaging of cortical bone porosity and trabecular architecture, custom macros for the image analysis programs ImageJ and CTAnalyser, and a macro for ImageJ that divides cortical area masks into Anterior, Posterior, Medial, and Lateral regional quadrants using the section centroid. The authors suggest the data will facilitate analysis of regional variation in pore distribution and geometry. Other major findings and results are discussed, and research study details are presented at length the report as well as in the 33 Appendixes.