Five days after the implantation, the 40 rats were evenly divided into five groups and injected with PBS, TMZ-FaPEC@siRNA, TMZ-PEC@siRNA, TMZ-FaPEC@SCR, and FaPEC@siRNA, respectively. Treatments were given every four days at the doses of 120 μg/kg TMZ and 1.6 μg/kg siRNA. The five injection points for each treatment were 4, 4.5, 5, 5.5, and 6 mm away from the dura, respectively, and the needle was kept still for 5 min before retraction. Twenty-five days after the first injection, Gd-DTPA (Bayer Schering Pharma AG, Berlin, Germany) was intravenously administered at a dose of 150 μL/kg, and then the rats were subjected to magnetic resonance imaging (MRI) for the measurement of tumor volume. T1-weighted sequence was employed to acquire images as reported.19 (link) The mean tumor volume (mm3) was calculated as π×a×b×c/2, in which a, b, and c represented coronal long diameter, coronal short diameter, and sagittal long diameter, respectively.