BAK1 and brain glioma: To further explore the signaling pathway of naltrindole-induced brain glioma apoptosis, JC-1 staining flow cytometry was used to analyze the changes in the mitochondrial membrane potential, and western blot analysis was used to analyze the changes in the expression levels of the relevant proteins, Bax, Bcl-2, Bcl-xL, Bak and cytochrome c (Fig. 3).