Figure 4. Dual B1R/B2R agonist treatment enhances the in vivo antitumor activity of carboplatin. (A) Kaplan–Meier survival curves of F98 glioma-bearing rats. F98 glioma cells (1 × 10⁴ cells) were inoculated on day 0. MRI scans were performed on day 9 in the animal groups (2−3 rats/group) to confirm the presence and size of tumors before the beginning of the treatments. On day 10, animals were treated with the vehicle, agonists alone or in combination (50 nmol/kg/min i.c; 0.5 ml over 5 min) followed by carboplatin (20 mg/kg; 1 ml over 10 min). Survival curves were compared with the log-rank test. (B) Pt-DNA adducts in tumors, tumor periphery and contralateral tissues from F98 glioma-bearing Fischer rats treated with carboplatin in combination or not with the B1R/B2R dimer agonist as above. Brain slices (100−200 mg) were collected 24h after the administration of the drugs and immediately snap frozen in liquid nitrogen. A diagram depicting how the schematic slices were taken is shown. Frozen rat brain tissues were cut into pieces and digested with RNase A and Proteinase K in the presence of SDS detergent. Genomic DNA was extracted by the phenol/chloroform method and its purity estimated from the 260/280 nm-absorbance ratio. DNA samples were then analyzed for their Pt content by ICP-MS as described in Côté et al.⁵P < 0.05 as determined by the Dunnett test; n = 3−4 animals per group.