Fig. 1

Celastrol treatment reduces infarct volume 3 days after middle cerebral artery occlusion (MCAO). a The structure of celastrol. b Experimental procedure for in vivo experiments. Stroke was induced in rats with permanent occlusion of the MCAO. Celastrol was intraperitoneally injected (1 mg/kg) at 0 and 24 h after ischemia. Three days after stroke, M1/M2 microglia markers and infarct volumes were measured with immunofluorescence and TTC staining, respectively. The adhesive removal test and modified Garcia scores were used to measure post-stroke sensorimotor functions 0, 3, 5, 7, and 10 days after cerebral ischemia. To confirm whether celastrol regulates microglial polarization in the brain after MCAO, brain sections were double-stained for Iba-1 (microglia) and CD206 (M2 marker) or CD16 (M1 marker) 10 days after stroke. ELISA analyses were used to detect the expression of serum IL-33 10 days after stroke. Immunohistochemistry was used to detect apoptotic neurons 10 days after stroke. c Representative TTC staining 3 days after MCAO. d Infarct volume in MCAO rats with or without celastrol. The data are presented as mean ± SD. ***P < 0.001 vs. control group. ^###P < 0.001 vs. MCAO group. e Representative images of cortex around infarct regions with NeuN- and TUNEL-staining 3 days after MCAO treatment with or without celastrol. Scale bar = 50 μm. f The quantification of NeuN and TUNEL double-labeled cells. The data are presented as mean ± SD. *P < 0.05, ***P < 0.001 vs. control group. ^###P < 0.001 vs. MCAO group. g Representative images of cortex around infarct regions with NeuN- and TUNEL-staining 10 days after MCAO treatment with or without celastrol. Scale bar = 50 μm. h The quantification of NeuN and TUNEL double-labeled cells. The data are presented as mean ± SD. *P < 0.05, ***P < 0.001 vs. control group. ^###P < 0.001 vs. MCAO group. n = 6 rats