Immunohistochemical labeling of activated caspase 3 and 9.

<p>A. Cleaved caspase 3 (red) and DAPI (blue) labeling of thin section of 2-week old untreated control tumor. B. Cleaved caspase 3 (red) and DAPI (blue) labeling of tumor tissue removed 2 h after treatment (400p, 15 kV, 100 ns). C. Cleaved caspase 9 (red) and DAPI (blue) labeling of 2 week old untreated control tumor. D. Cleaved caspase 9 (red) and DAPI (blue) labeling of tumor tissue removed 2 h after nsPEF treatment. Note how the tumor nuclei in B and D have shrunk after treatment, indicating pyknosis. E. Summary of the analysis of 3–7 thin sections taken from one control tumor 14 days after injection and 2 treated tumors fixed 2 h after 400 p, 15 kV. Bars indicate SEM. The difference in activated caspase label between pulsed tissue and controls is highly significant with p = 0.005.