〔Abstract〕 Objective To explore the mechanism of exosomes derived from glioma cells on cell proliferation and apoptosis. Methods The U251 exosomes were extracted by high-speed centrifugation.The morphology of exosomes was analyzed by electron microscopy and nano particle size, and the characteristic protein expression of exosomes was detected by Western blot.30 μl of exosome suspension with concentration of 100 μg/ml(exosome group) or equal amount of medium without exosomes(control group) was added to U251 cell culture medium, and the double fluorescence staining method was used to verify whether exosomes could enter U251 cells.The changes of cell proliferation and apoptosis were detected by CCK-8 and flow cytometry.The miRNAs differentially expressed in U251 exosomes and human astroglial cells were screened by RT-PCR.Finally, the U251 cells were transfected with miR-NC,miR-125 b mimicsor miR-125 b inhibitor, exosomes were extracted and added into cell culture medium, and the proliferation and apoptosis of U251 cells were detected by CCK-8 and flow cytometry. Results The exosomes isolated from U251 cells were round or oval vesicular bodies, with the diameter around 100 nm and rich in CD63 and CD9 proteins.After adding exosomes suspension in U251 cell culture medium, exosomes could bepackaged by U251 cells.CCK-8 and flow cytometry showed that the proliferation activity of exosomes was higher than that of the control group, and the apoptosis rate was lower.RT-PCR showed that the content of miRNA-125 b in U251 cells exosomes was higher than that in human astrocytes exosomes.After transfection of U251 cells with miR-NC,miR-125 b mimicsor miR-125 b inhibitor, the exosomes of the three groups were extracted and added into U251 cell culture medium.The proliferative activity of miR-125 b inhibitor group was lower than that of miR-NC group, and the apoptosis rate was higher than that of miR-NC group.The cell proliferation activity of miR-125 b mimics group was higher than that of miR-NC group, and the apoptosis rate was lower than that of miR-NC group.The differences were statistically significant(P<0.05). Conclusion By enriching miR-125 b, exosomes derived from glioma cellscan promote the proliferation of glioma cells and inhibit cell apoptosis.