Figure 1 Electron microscopic observation and particle size analysis of exosomes
Note： A， Exosome observed under electron microscopy has a diameter of approximately 100 nm and is spherical in shape （the scale bar is 100 nm）； B， Particle size analysis of exosome suspension.

Figure 2 MCA blood flow changes during MCAO model establishment and TTC staining of the cerebral infarction area
Note： A， The black arrow indicates the middle cerebral artery （MCA）， which is Y-shaped； B， short-duration electrocoagulation （approximately 2-3 s）， during which blood flow begins to decrease；C， continued electrocoagulation （cumulative approximately 5-6 s）， with blood flow largely interrupted；D， sufficient electrocoagulation （cumulative approximately 8-10 s）， resulting in complete vascular occlusion； E， 2，3，5-triphenyltetrazolium chloride （TTC） staining results of brain sections in the middle cerebral artery occlusion （MCAO） model group， the white area indicated by the black arrow is the infarcted area. The scale bar in A-D indicates 3 mm； The scale bar in E indicates 5 mm.

Figure 3 Analysis of neurological deficit scores and the percentages of cerebral infarction volume in each group of mice
Note： A， Neurological Longa scores of each group of mice； B， 2，3，5-triphenyltetrazolium chloride （TTC） staining results of brain sections in each group of mice， each column contains six slices representing the complete brain of one mouse， normal brain tissue was red， while brain tissue in the infarcted area was white； C， The percentages of brain infarction volume in each group of mice. The sham operation group （Sham） only exposed the middle cerebral artery without electrocoagulation of the vessel； the model group （MCAO） used high-frequency surgical forceps to electrocoagulate the middle cerebral artery at a power of 8 W； the model + normal saline group （MCAO+NaCl） first injected 100 μL of normal saline through the tail vein， and then performed electrocoagulation modeling； the model + exosome group （MCAO+EXO） first injected 100 μL of exosomes （9.5×10¹¹ particles per mL） from the culture supernatant of human amniotic mesenchymal stem cells （hAMSCs） through the tail vein， and then performed electrocoagulation modeling. There were eight mice in each group. ^??P＜0.01， ^???P＜0.001.

Figure 4 HE staining of brain tissue sections from each group of mice to observe neuronal morphology
Note： The sham operation group （Sham） only exposed the middle cerebral artery without electrocoagulation of the vessel； the model group （MCAO） used high-frequency surgical forceps to electrocoagulate the middle cerebral artery at a power of 8 W； the model + normal saline group （MCAO+NaCl） first injected 100 μL of normal saline through the tail vein， and then performed electrocoagulation modeling； the model + exosome group （MCAO+EXO） first injected 100 μL of exosomes （9.5×10¹¹ particles per mL） from the culture supernatant of human amniotic mesenchymal stem cells （hAMSCs） through the tail vein， and then performed electrocoagulation modeling. The scale bar of the ×40 field of view in the first row of the figure is 50 μm， and the scale bar of the ×100 field of view in the second row is 20 μm. The area indicated by the black arrow is the region of cytoplasmic vacuolar degeneration， and the area indicated by the blue arrow is the region of nuclear pyknosis and fragmentation.

Figure 5 Microcolorimetric assays of Fe²⁺， MDA， total GSH， GSSG and GSH contents in the brains of each group of mice
Note： A-E， Contents of Fe²⁺， malondialdehyde （MDA）， total glutathione （total GSH）， oxidized glutathione （GSSG）， and reduced glutathione （GSH） in the brains of mice from each group. Reduced GSH was calculated as the difference between the contents of total GSH and GSSG. The sham operation group （Sham） only exposed the middle cerebral artery without electrocoagulation of the vessel； the model group （MCAO） used high-frequency surgical forceps to electrocoagulate the middle cerebral artery at a power of 8 W； the model + normal saline group （MCAO+NaCl） first injected 100 μL of normal saline through the tail vein， and then performed electrocoagulation modeling； the model + exosome group （MCAO+EXO） first injected 100 μL of exosomes （9.5×10¹¹ particles per mL） from the culture supernatant of human amniotic mesenchymal stem cells （hAMSCs） through the tail vein， and then performed electrocoagulation modeling. There were eight mice in each group. ^nsP >0.05， ^??P<0.01， ^???P<0.001， ^????P<0.000 1.

Figure 6 Detection and analysis of mRNA and protein expression of NRF2， SLC7A11 and GPX4 in the brains of each group of mice
Note： A-C， mRNA transcription levels of nuclear factor-erythroid 2-related factor 2 （NRF2）， solute carrier family 7 member 11 （SLC7A11）， and glutathione peroxidase 4 （GPX4） in the brains of mice from each group. D-F， Relative protein expression levels of NRF2， SLC7A11， and GPX4 in the brains of mice from each group. G， Western blotting images of NRF2， SLC7A11， GPX4， and GAPDH. The sham operation group （Sham） only exposed the middle cerebral artery without electrocoagulation of the vessel； the model group （MCAO） used high-frequency surgical forceps to electrocoagulate the middle cerebral artery at a power of 8 W； the model + normal saline group （MCAO+NaCl） first injected 100 μL of normal saline through the tail vein， and then performed electrocoagulation modeling； the model + exosome group （MCAO+EXO） first injected 100 μL of exosomes （9.5×10¹¹ particles per mL） from the culture supernatant of human amniotic mesenchymal stem cells （hAMSCs） through the tail vein， and then performed electrocoagulation modeling. There were eight mice in each group. ^?P<0.05， ^??P<0.01， ^???P<0.001， ^????P<0.000 1.