【Animal modeling】-Combined with high-resolution MRI and micro-CT to evaluate the repairing effect of Taohong Siwu Decoction on femoral head necrosis in rabbits

  OBJECTIVE: To establish a rabbit model of steroid-induced necrosis of the femoral head (SIONFH), and to evaluate the repairing effect of Taohong Siwu Decoction (THSWD) on the damage of SIONFH microscopic bony structure combined with high-resolution MRI and micro-CT.

  Methods: Twenty-five New Zealand rabbits were randomly divided into 3 groups: 5 in the normal group, 10 in the model group and 10 in the traditional Chinese medicine group (Taohong Siwu Decoction group). Steroid-induced femoral head necrosis model, the traditional Chinese medicine group was given 0.3 g/kg Taohong Siwu Tang suspension by gavage, and the normal group and model group were given an equal volume of ultrapure water. On the 8th week of the experiment, high-resolution MRI examination of the femoral head with a 3.0 T high-resolution magnetic resonance imager was performed, and hematoxylin-eosin staining and microCT examination were performed on the femoral head.

  Results: 1) In the high-resolution MRI, low signal bands were seen in the femoral head of the model group; the shape of the femoral head in the traditional Chinese medicine group tended to be normal, there was a small area of low density in the femoral head near the epiphysis, and most of the bone tissue gray values were normal. Compared with the normal group, the ROE value of the former structure parameter increased and the ROE/NR ratio increased. Compared with the model group, the traditional Chinese medicine group had a decrease in ROE value and a decrease in the ROE/NR ratio, and the difference was significant (P<0.05). 2) In the hematoxylin-eosin staining, part of the trabecular bone fracture, bone cell nuclear pyknosis, empty trabecular bone lacuna, and bone marrow cell necrosis were seen in the model group, with significant differences (P<0.05). It can be seen that the osteogenic activity is still relatively active, and the trabecular bone shape is better. 3) In micro-CT, compared with the normal group, the values of BV/TV, Conn.D., SMI, Tb.N, Tb.Th and BS/BV and Tb.Sp of the model group decreased in the former group, and the values of BS/BV and Tb.Sp increased. In the traditional Chinese medicine group, BS/BV and Tb.Sp were significantly lower than those in the model group, and Conn.D., SMI, and Tb.N were increased, and the difference was significant (P<0.05). ROI three-dimensional reconstruction showed that the trabecular bone disorder in the model group, It can be seen that there is widespread fracture and less bone; the traditional Chinese medicine group has relatively improved bone quality and local repair of trabecular bone.

  Conclusion: Taohong Siwu Decoction can promote the repair of microscopic bone structure and the improvement of biomechanical environment in rabbit SIONFH model.