Figure 1.

Effect of TMZ treatment on U251 tumor morphology, apoptosis, and proliferation. (A) T₁- and T₂-weighted MRI at ~2 and ~3 weeks post tumor implantation, respectively, depicting tumor sizes in untreated and TMZ treated U251 tumor bearing rats. The measurements at ~2 weeks and ~3 weeks were, respectively, made by T₁ and T₂ MRI contrast enhacement. In the treated group, the rats were imaged at 12.6 ± 0.5 and 22.8 ± 0.7 days, whereas in the untreated group the rats were imaged at 12.4 ± 2.2 and 22.0 ± 3.3 days. (B) Tumor volume in treated and untreated U251 bearing rats at ~2 and ~3 weeks post tumor implantation, where the difference between treated and untreated groups were significant at later stages (*p = 0.01). (C) Ki-67 and cleaved caspase-3 staining in untreated and TMZ treated U251 tumor bearing rats. Arrows point to brown colored positive DAB staining. (D) Percentage of cells showing positive staining for Ki-67 and Cleaved Caspase-3. In treated vs. untreated tumors, Ki-67 shows a significant decrease in proliferative index (*p = 0.025) and cleaved caspase-3 shows a significant increase in apoptotic index (#p = 0.001).