Changes of AQP2 expression in the kidney of rat sepsis model / 中国小儿急救医学

ABSTRACT

Objective To investigate the expression and the significance of AQP2 in the kidneys of septic rats. Methods Sixty-four Wistar rats of 6 weeks were randomly divided into two groups sham group and the septic model group. Septic models were made by cecum ligation perforation (CLP). Fach group was divided into 3-hour,6-hour,12-hour and 24-hour subgroups,with 8 rats in each. The urine,blood and kidney sampies were collected. The urine volume ,urine osmotic pressure and renal function were observed. The expressions of AQP2 protein in rats' kidneys were determined by using immunohistochemical method and the expressions of AQP2 mRNA with real-time PCR. The pathological changes of the kidneys were observed under light microscopy. Results After CLP,urea volume of Wistar rats in septic model group decreased and urine osmotic pressure increased at 3 hours; urea volume gradually increased and urine osmotic pressure decreased at 6 hours; Serum Cr and urea nitrogen began to increase at 6 hours and reached the peak at 24 hours. The longer the time lasted after CLP,the more serious the injury of kidney became,which was mainly manifested as that the space between the epithelial cells of the tubular wall disappeared,nucleus disappeared,glomerular loops fused,and cell structure was unclear. Renal mesenchymal was infiltrated with inflammatory cells. AQP2 mRNA expression increased at 3 hours,decreased at 12 hours and 24 hours ,AQP2 protein expression decreased at 12 hours,with the lowest at 24 hours,which were significantly different from those of the sham groups(P<0.05). Conclusion AQP2 may regulate the water metabolism of septic rats' kidney. The decreased AQP2 protein expression is one of the main pathological mechanisms that results in dysfunction of urine concentration in sepsis.