U87GM orthotopic model

The BALB/c nude mice (male, 4–6 weeks old) used in this study were supplied by the Department of Experimental Animals (Daping Hospital, Third Military Medical University, Chongqing, China). All animal use protocols were performed according to the international principles of laboratory animal care and were approved by the Animal Use Subcommittee of Daping Hospital, Third Military Medical University. Anesthetized mice were mounted dorsally with their heads fixed in a stereotaxic apparatus (RWD Life Science, Shenzhen, China). A 5.0 µL cell suspension containing 5 × 10⁵ U87MG cells was injected into the brain using a 20.0 µL microsyringe. The microsyringe was fixed stereotactically to vertically penetrate 4.0 mm into the brain mass, 2.0 mm to the right of the midline suture and 2.0 mm posterior to the outer canthus and was then retracted 0.5 mm. The cell suspension was then injected slowly over a period of 5 min. After injection, the microsyringe was held in place for 8 min and then retracted.