Figure 4. MWNTs mediated photothermal ablation reduces tumor volume and cancer-induced bone destruction.

(A) Tumor growth curves for mice treated with saline, laser alone, 10 μg MWNTs, 1 μg MWNTs + laser, and 10 μg MWNTs + laser. There were no statistically significant differences (P > 0.05) in the mean tumor volume among the groups treated with saline, laser alone and 10 μg MWNTs, but tumor volume in the group treated with 10 μg MWNTs + laser was significantly smaller (P < 0.01). The effect of suppression tumor growth was attenuated with decreased dosage of MWNTs of 1 μg. 1 μg MWNTs + laser produced modest suppression in tumor volume, which was significantly larger than that in the group of 10 μg MWNTs + laser (P < 0.05). The bars represent means ± s.d. (n = 5). (B) Micro-CT images of tumor-bearing tibiae showed changes of bone structure subjected to treatment with saline (rank a), laser alone (rank b), (c) 10 μg MWNTs (rank c), 1 μg MWNTs + laser (rank d) and 10 μg MWNTs + laser (rank e) from total bone, transverse-section (X-section) and cross-section (Y-section) views respectively. In the groups treated with saline (a), saline + laser (b) and 10 μg MWNTs (c), the bone structure was all severely destroyed and massive osteosclerotic growth was observed. However, in the groups treated with 1 μg MWNTs + laser (d), and 10 μg MWNTs + laser (e), there was only mild bone destruction. Especially in the groups treated with 10 μg MWNTs + laser, the bone structure was significantly protected. (C) Tumor-bearing tibiae treated with 10 μg MWNTs + laser showed a statistically significant decrease in bone volume compared with those treated with saline, laser alone and 10 μg MWNTs (P < 0.05), but 1 μg MWNTs + laser led to only a slight reduction in bone volume compared with the other three groups (P > 0.05). The bars represent means ± s.d. (n = 5).