CNR2 and Abnormal renal physiology: Eight studies [22, 26, 36, 37, 44, 46, 47, 53] reported Scr found that the activation of CB2 group could significantly reduce Scr in renal dysfunction animals compared with the control group (Fig. 5B, 8 items, n = 136; SMD, − 0.97; 95% CI − 1.83 to − 0.11; P = 0.03; I2 = 70%).