2022, Vol. 26 ›› Issue (18): 2874-2880

Application of micro-CT in rabbit tibial osteomyelitis modeling

Li Yufan1, 2, Lin Mingyue1, 2, Wang Chenxin1, 2, Zhang Rui1, 2, Li Yubao1, 2, Chen Li1, Zou Qin1, 2   

Abstract: BACKGROUND: Micro-computed tomography (micro-CT) is a non-destructive three-dimensional imaging technology, which can clearly observe the internal microstructure of a sample without damaging. Its resolution is very high, and the spatial resolution reaches 1-10 μm, even 0.25 μm in some advanced models. Micro-CT has been widely used for data analysis and image processing in bone tissue engineering research.   
OBJECTIVE: To analyze the inflammation-induced structural changes of the rabbit tibia using micro-CT to verify whether a rabbit model of osteomyelitis is successfully established.
METHODS: Twenty New Zealand white rabbits were selected, five of which were taken as the control group, and the remaining fifteen rabbits were used to establish the right tibia osteomyelitis model. After modeling, imaging characterization was conducted in the rabbit models (n=5 at each time point) at 2, 4, and 6 weeks. Feeding, pattern of sleeping, and wound healing in rabbits were observed postoperatively. X-ray in vivo imaging was used to detect the changes of bone tissue during the modeling of rabbit tibial osteomyelitis. Micro-CT was used to scan the affected limb layer by layer to obtain the corresponding cross-sectional images, followed by three-dimensional reconstruction. Bone volume and bone mineral density were calculated in each group.   
RESULTS AND CONCLUSION: Gross observation: Purulent liquids and tissues could be found around the modeling site from the 4th week, and inflammatory reactions occurred. Large-area hyperostosis was observed at the 6th week. X-ray imaging observation: the swelling degree and periosteal reaction in the model group became gradually serious over time, and dead bones proliferated a lot. Micro-CT analysis: The cross-sectional images showed that osteoporosis and hyperplasia gradually appeared during the first 4 weeks. After 6 weeks of modeling, the rabbit cortical bone was significantly damaged and seriously proliferated, and inflammation spread to the medullary cavity. Through the three-dimensional reconstructions, a mass of dead bones formed around the bone window at the 6th week, accompanied by severe periosteal reaction, obvious swelling, and serious hyperostosis. Cancellous bone structure was seriously damaged and deformed, and trabecular bones were largely damaged and lost. Notably, the inflammation spread to the whole tibia. In addition, there was significant damage to endosteum and facies articularis ossium, and the cortical bone proliferated with voids. Findings from bone parameter calculation indicated that the bone volume was increased, the cortical bone mineral density was decreased, and the cancellous bone mineral density was increased after inflammation. To conclude, micro-CT can be used for cross-sectional imaging, three-dimensional reconstruction, and quantitative analysis of bone parameters. Micro-CT scan prominently makes up for the shortcomings of X-ray and gross observation, and provides experimental basis and new ideas for bone tissue engineering research related to osteomyelitis.
Key words: micro-computed tomography, tibial osteomyelitis, bone microstructure, three-dimensional reconstruction, quantitative analysis, rabbit