Knockdown of circHIPK2 expression alleviated the astrocyte dysfunction induced by CUS. a Colocalization of circHIPK2 and GFAP-positive cells in mouse hippocampi. Green represents circHIPK2; red, GFAP; blue, DAPI. Scale bar, 10 μm. b circHIPK2 siRNA microinjection significantly attenuated CUS-induced decreased GFAP expression. Mice were microinjected with the circCon or circHIPK2 siRNA lentivirus followed by CUS treatment. N = 6 mice/group. c Effect of circHIPK2 knockdown on astrocyte dysfunction induced by CUS. Representative images of astrocyte immunostaining for GFAP in mouse hippocampi, followed by 3D reconstruction and Sholl analysis. Scale bars, 50 μm. d Quantification of GFAP-positive cells per square millimeter in mouse hippocampi. N = 4 mice/group. e–g Average branch number (e), total branch length (f), and total branch volume (g). n = 4 mice/group, 40 cells/group. ***p < 0.001 vs. the circCon control group. #p < 0.05, ##p < 0.01 and ###p < 0.001 vs. the CUS-treated circCon group using one-way ANOVA followed by the Holm-Sidak test.