CNR2 and Abnormal renal physiology: Four studies [22, 26, 37, 52] reported BUN found that the knockout or blockade of CB2 group could little or no change BUN in renal dysfunction animals compared with the control group (Fig. 7A, 4 items, n = 54; SMD, 0.99; 95% CI 0.08 to 1.90; P = 0.03; I2 = 56%).