highly significantp < 0.001
Five studies, 7 studies, 5 studies, 12 studies, 17 studies, 7 studies, and 2 studies were included to assess the effect of treatment on blood glucose levels at 1 week, 2 weeks, 3 weeks, 1 month, 2 months, 3 months, and 6 months, respectively, all of which showed a highly significant hypoglycemic effect in the MSC-treated group (1 week: SMD = − 1.484, 95%CI − 2.586 to − 0.381, p < 0.001; I 2 = 80.6%; 2 weeks: SMD = − 2.312, 95%CI − 3.743 to − 0.882, p = 0.002, I 2 = 89.6%; 3 weeks: SMD = − 4.007, 95%CI − 6.472 to − 1.541, p = 0.001, I 2 = 92.1%; 1 month: SMD = − 1.740, 95%CI − 2.660 to − 0.821, p < 0.001, I 2 = 83.8%; 2 months: SMD = − 1.830, 95%CI − 2.633 to − 1.028, p < 0.001; I 2 = 86.0%; 3 months: SMD = − 1.649, 95%CI − 2.838 to − 0.461, p = 0.007; I 2 = 84.6%; 6 months: SMD = − 3.045, 95%CI − 5.895 to − 0.195, p = 0.036; I 2 = 76.4%).