Effects of oral administration of potassium 2,5-diacetoxyphenyl sulfonate (DAPS) on the progression, angiogenesis and apoptosis of tumors established in rats by subcutaneous implantation of rat glioma C6 cells (5 × 10
cells). Treatment began once the presence of a tumor was verified on the fifth day after glioma cell implantation (arrow in panel A). Tumors were removed after 10 days of treatment with vehicle (VEH, tap water; n = 8) or DAPS (200 mg/kg/d; eq. to 0.73 mmol/kg/d; n = 10) by oral gavage. Panel A shows the time-course of subcutaneous glioma size in rats treated with vehicle or DAPS. Panel B shows representative images of macroscopic aspect of tumors excised from rats treated with vehicle or DAPS while the quantification and comparison of the volumes and weights are shown in the same row. Panel C shows representative images illustrating the intense leukocyte extravasation and infiltration observed in peritumoral vessels of gliomas obtained from vehicle-treated rats that is markedly reduced in gliomas from rats treated with DAPS. Panel D shows representative images illustrating the intense vascularization in tumors from vehicle-treated rats which is notably reduced in DAPS-treated rats, as confirmed by functional vessel quantification displayed at the right side. Panel E shows representative images illustrating the scarce presence of apoptotic nuclei detected by TUNEL assay in sections of tumors from vehicle-treated rats that markedly increased in DAPS-treated rats, as confirmed by quantification of the percentage of tumoral apoptotic nuclei displayed at the right side. The data are expressed as the mean ± SEM: *p < 0.05; **p < 0.01; ***p < 0.001 vs. VEH by unpaired Student’s t test.