The incidence of acute kidney injury following cardiac arrest and cardiopulmonary resuscitation in a rat model

Abstract

Objective: In the current study, we investigated the incidence of acute kidney injury (AKI) induced by cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) and whether such an AKI can recover spontaneously in rats.

Methods: We used transesophageal alternating current stimulation to establish 7 min of CA rat model followed by conventional CPR. The experimental rats were randomly divided into three groups (n = 20 per group) according to the different time points after restoration spontaneous circulation (ROSC): the ROSC 24 h, ROSC 48 h, and ROSC 72 h group. The diagnosis of rat AKI refers to the 2012 KDIGO adult AKI diagnostic criteria. The severity of AKI quantified by the serum creatinine (SCR), blood urea nitrogen (BUN) levels and histological features of renal tissue.

Results: The incidence rates of AKI in ROSC 24 h, ROSC 48 h, and ROSC 72 h group were 65%, 45%, and 42.9%. Moreover, the values of SCR and BUN were highest at ROSC 24 h, and then gradually decreased with the time of ROSC. The histological changes of the renal tissues such as glomerular collapse, renal tubular cell swelling, and inflammatory cell infiltration had also observed.

Conclusion: The incidence of AKI in rats was high after suffering from CA and CPR, but renal function improved with the prolongation of ROSC time, indicating the ability of the kidney to self-repair.

Keywords: Acute kidney injury; cardiac arrest; cardiopulmonary resuscitation; ischemia-reperfusion injury; rat.

Figure 1.

Changes in kidney function in rats after CA and CPR. Levels of (A) serum creatinine (SCR) and (B) blood urea nitrogen (BUN) were determined 24 h, 48 h, and 72 h after ROSC. SCR and BUN levels in the sham group were significantly lower than those in the model group. Data were expressed as mean ± SD #p < .01, ##p < .05 and ###p < .05. SCR: serum creatinine; BUN: blood urea nitrogen; CA: cardiac arrest; CPR: cardiopulmonary resuscitation.

Figure 2.

Light microscopy results. (A) sham-operated rat showed no tubular injury (magnification, x40). (B) After rat ROSC for 24 h, The kidney was extensively destroyed by excessive monocytes, increases in tubular necrosis, and tubular dilation (magnification, x100). (C,D) After rat ROSC for 48 h (magnification, x40) and 72 h (magnification, x100), there remained major tubular necrosis and cast formation. The arrows denote tubular necrosis and cast formation, ‘H’ denotes excessive monocytes. (E) The renal damage score was highest in the ROSC 24 h group compared with that in the ROSC 48 h and ROSC 72 h group. Results are expressed as mean ± SEM (n = 6 for each group) #p < .05, ##p < .01.