Moreover, exosomes extracted from BDNF-pretreated MSCs could effectively promote functional recovery and neurogenesis of rats after traumatic brain injury, the mechanism may be related to the high expression of miR-216a-5p [63], and exosomes derived from BDNF-overexpressing 293 T cells were reported to have a stronger neuroprotective effect than that from cells without overexpression of BDNF [64, 65]. The gene discussed is BDNF; the disease is injury.