Fig. 6: Delivery of TGF-β1-enriched EVs augments M2 polarization of microglia and mitigates postischemic motor coordination impairment in stroke mice.

A, B Quantitative analysis of M2 polarization of microglia cells (CD206, green) in the ischemic striatum at post-MCAO day 7 by immunofluorescence staining in the three groups: MCAO control, MCAO with EV treatment, and MCAO with si-EV treatment. EV infusion increases M2 polarization rates of resident microglial cells in the ischemic striatum compared with the si-EVs group (n = 5). C At post-MCAO day 7, flow cytometry of ischemic hemispheres showing a significant increase of M2 microglial cells (CD45^intCD11b⁺CD206⁺) in the EV treatment group compared to the MCAO control and the MCAO si-EV treatment group (n = 4). Delivery of EVs reduces postischemic motor coordination impairment. Motor coordination was evaluated using the rotarod test (D), balance beam test (E), tightrope test (F), corner turn test (G), and paw slips recording (H) 1 day before stroke (pre) as well as 2, 5 and 7 days after stroke. All animals were accordingly trained before the induction of stroke in order to ensure proper test performance (n = 5). Data are expressed as mean ± SD. NS no significance, *p < 0.05, **p < 0.01, and ***p < 0.001. EVs extracellular vesicles, MCAO middle cerebral artery occlusion.