*2.2. Prevention of Osteonecrosis by Taurine in a Glucocorticoid-Administered Rabbit Osteonecrosis Model*

After preparing a glucocorticoid-administered rabbit osteonecrosis model, taurine was injected intravenously, and its inhibitory effect on osteonecrosis development was determined. In none of the animals in MP−/TAU− group, were there any sites showing necrosis of medullary haematopoietic cells or fat cells, and no empty lacunae or condensed nuclei in osteocytes were found. In 12 of 15 rabbits in the MP+/TAU− group, osteonecrosis was found. In 4 of 15 rabbits in the MP+/TAU+ group, necrosis of medullary haematopoietic cells or fat cells and empty lacunae or condensed nuclei in osteocytes were noted at some sites, and the osteonecrosis development rate was 20% (*p* < 0.05 vs. MP+/TAU−) (Figure 2). Since the decrease in the osteonecrosis development rate was significant, taurine was suggested to have inhibited osteonecrosis development in this experiment.

**Figure 2.** Osteonecrosis inhibition with intravenous administration of taurine in a glucocorticoid-induced rabbit osteonecrosis model. (**a**) MP−/TAU−, (**b**) MP+/TAU−, (**c**,**d**) MP+/TAU+. Osteonecrosis was found in 12 of 15 rabbits of MP+/TAU− group (**b**). In 4 of 15 rabbits of the MP+/TAU+ group, some portions showing necrosis of medullary haematopoietic cells or fat cells and empty lacunae or condensed nuclei in osteocytes were found (**d**). The osteonecrosis development rate was 20%, representing a significant inhibition of osteonecrosis as compared with the MP+/TAU− group (*p* < 0.05). Scale bar: 200 μm.
