“…Six studies reported types of exosomes but did not report specific sources ( 31 , 32 , 38 , 40 , 45 , 46 ). The transplantation route of exosomes included tail vein ( 19 – 21 , 29 – 32 , 34 – 50 , 52 – 56 ), intranasally ( 33 ) and subcutaneous ( 51 ), and one study did not report the route of exosome transplantation ( 28 ); the time transplantation of exosome ranged from 0 ( 19 , 20 , 31 , 38 , 41 , 44 – 47 , 49 ) to 24 h ( 42 , 43 ) after modeling, one study did not report the time of exosome transplantation ( 40 ); dose of exosomes ranged from 20 ( 29 ) to 200 μg ( 28 , 30 – 33 , 36 – 38 , 41 , 43 , 45 – 49 , 53 , 56 ); the control group includes PBS ( 19 – 21 , 28 – 32 , 34 , 35 , 38 , 39 , 41 , 43 – 51 , 53 – 56 ), saline ( 33 , 36 , 37 , 40 , 42 ), and blank ( 52 ). Basic information of the study subjects was summarized in Supplementary Table 2 .…”