Steroid-associated osteonecrosis animal model in rats

Zheng, Li-Zhen; Wang, Jia-Li; Kong, Ling; Huang, Le; Tian, Li; Pang, Qian-Qian; Wang, Xin-Luan; Qin, Ling

To determine the trabecular architecture, the tibiae from week 6 of each group were fixed in buffered formalin for one week and then were scanned using an animal micro-CT system (mCT-40; Scanco Medical, Brüttisellen, Switzerland). The trabecular bone with thickness of 2 mm and 2 mm from the growth plate was used as the ROI for analysis. The spatial resolution was set at 15 mm. A threshold of 220 HU and a low-pass Gaussian filter (Sigma Z 0.8, Support Z 1) were used to define mineralised tissue from the background signal [18] . The bone mineral density (BMD), bone tissue volume fraction (BV/TV), structure model index (SMI), connective density (Conn. D.), trabecular number (Tb. N), trabecular thickness (Tb. Th) and trabecular separation (Tb. Sp) were quantified [19] .