AQP1 and acute kidney injury: The contents of serum AQP1, P53, and P21 protein are elevated in septic AKI, and a large amount of AQP1, P53 and P21 proteins filtered from the glomerular filtration membrane and exceeded the reabsorption capacity of renal tubules, resulting in elevated levels of AQP1, P53 and P21 in urine.