Role of Different Central Venous Pressure Levels in Septic-associated Acute Kidney Injury
Objective To explore the role of different CVP levels in the occurence and development of sepsis-associated acute kid-ney injury(SA-AKI).Methods Sepsis model was induced using the cecal ligation and puncture(CLP)method for 24h in male SD rats,with a sham group as the control.The rats in two groups were intravenously infused with Ringer's solution to induce an increase in CVP to 10,15 and 20mmHg,respectively.The hemodynamic parameters including mean arterial pressure(MAP),heart rate(HR),and arterial blood lactate(Lac)were dynamically monitored in rats.And side stream darkfield imaging(SDF)technique was used to de-tect the renal cortex microcirculation perfusion parameters including perfused small vessel density(PVD)and microvascular flow index(MFI).Renal injury markers including serum creatinine(CRE),urine neutrophil gelatinase associated lipocalin(NGAL),renal inflam-matory factor interleukin-6(IL-6)levels and renal histopathological changes were also detected.Results Compared with the sham group,the MAP of CLP rats significantly decreased,while HR and Lac significantly increased(P<0.05).The renal PVD and MFI were significantly decreased(P<0.05),while serum CRE,urine NGAL,and renal IL-6 were significantly increased(P<0.05).Com-pared with CVP 10mmHg,the PVD and MFI of CLP rats were significantly decreased at CVP 20mmHg(P<0.05);The PVD and MFI of sham group at CVP 15mmHg and 20mmHg were significantly lower than those of the CVP at CVP 10mmHg(P<0.05).The IL-6 of CLP rats at CVP 15mmHg was significantly higher than that at CVP 10mmHg(P<0.05),and the IL-6 levels at CVP 20mmHg were significantly higher than at CVP 15mmHg(P<0.05).In CLP rats,increasing CVP led to cortical and medullary edema,vacuolar degen-eration of renal tubular epithelial cells,loss of brush borders,tubular obstruction,and disappearance of Bowman's space;medullary ede-ma was more pronounced than in the cortex.In the sham group,glomerular and tubular swelling occurred at CVP 20mmHg,and Bowman's space became narrower.Conclusion Excessive CVP levels can decrease renal cortical microcirculation perfusion and promote the acti-vation of local inflammation and renal tissue edema in CLP rats,which exerting a detrimental effect during the process of S-AKI.