Creating Mice Mode Of Sepsis-induced AKI And Observing The Change And Effect Of Inflammation Mediators

Objective: Sepsis is the leading cause of death in critically ill patients, and the incidence of sepsis is increasing. The rate of severe sepsis during hospitalization almost doubled during the last decade and is considerably greater than previously predicted. Sepsis causes multiorgan failure, including acute kidney injury (AKI). The occurrence of AKI in the intensive care unit (ICU) was approximately 6%, the most frequent contributing factor to AKI being sepsis (50%). Other reports showed that between 45% and 70% of all AKI is associated with sepsis. And the mortality rate of sepsis-induced AKI is much higher, at over 70%. Now, inflammation mediators play an important role in ischemia-reperfusion cause of AKI. But, we are not very clear whether the inflammation mediators is also play an important role in sepsis-induced AKI.The aim of our research is to creat a clinically relevant mice mode of sepsis-induced AKI and to observe the change of inflammation mediators in it and the effects on it.Methods: Our study created a clinically relevant cecal ligation and puncture(CLP) model to mimic sepsis-induced AKI. Sixty healthy C57BL/6 male mice were divided into 3 groups by random: group I, normal group (n=12), only collected blood by digging the eyeball. Group II, sham group (n=24), the cecum was isolated but neither ligated nor punctured. Group III (n=24), for the CLP surgery. After the surgery, 30 ml/kg body wt of prewarmed(37℃) normal saline was given subcutaneously to the mice in sham group and CLP group and then received antibiotic and fluid therapy subcutaneously (imipenem/cilastatin, 25 mg/kg in 1ml of normal saline at 3h, 15h, 27h, 39h, 51h after surgery). 6h, 12h, 24h after surgery, blood was collected by digging the eyeball in sham group and CLP group. Blood serum was stored in-80℃and serum creatinine, blood urea nitrogen(BUN), IL-1, IL-6, TNF-αwere measured by ELISA. Take the peritoneal fluid and kidney. The 10% formalin-fixed, paraffin-embedded kidney sections were prepared for observation by light microscopy. At last mice were sacrificed.Statistical analysis was performed using SPSS 13.0 software package. P<0.05 was considered significant for all statistical analyses. Data were expressed as mean±SD. The results in the same hour but between different groups were analyzed using either one-way ANOVA. The comparison between multiple variables were using LSD-t test.Results:1 The general response after surgeryThe mice in CLP group were analepsia later than other groups, then depressed, shivering, tachypnea, dyspnea, secretion in angle of eye, before death it was dyspnea, shivering, body stiffness. In the abdominal, we will see purulence and uprightness effusion and bowels edema. The mice in Sham group were better than that in CLP group.2 General observation of kidney, Histological changes (hematoxylin-eosin staining) and Renal pathology scoresWe can see more bloodshot kidney in CLP group than sham group.Histological changes: Normal and sham group, nothing abnormal were detected. CLP group, glomerular and tubular hyperemia, tubular epithelial swelling and vacuolar degeneration.Renal pathology scores: After 6h, 12h, 24h of surgery, compared with sham group, the CLP group's renal pathology score was increased(P<0.05). There was no difference in CLP group (P>0.05) in 6h, 12h, 24h after surgery and the same result was in sham group (P>0.05).3 Bacterial abundance in peritoneal fluidThe result in CLP group was above 105 cfu/ml and in normal and sham group nothing was found.4 The level of creatinine in serumAfter 6h of surgery, compared with sham and normal group, the level of serum creatinine in CLP group was significant increased (P<0.05), there was no difference between sham group and normal group (P>0.05). After 12h and 24h of surgery, there was no difference between CLP group , sham and normal group (P>0.05). There was no difference in CLP group (P>0.05) in 6h, 12h, 24h after surgery5 The level of BUN in serumAfter 6h, 12h and 24h of surgery, compared with sham and normal group, the level of serum BUN in CLP group was significant increased (P<0.05), there was no difference between sham group and normal group (P>0.05). There was no difference in CLP group (P>0.05) in 6h, 12h, 24h after surgery.6 The level of IL-1 in serumAfter 6h, 12h and 24h of surgery, compared with sham and normal group, the level of IL-1 in CLP group was significant increased (P<0.05), there was no difference between sham group and normal group (P>0.05). There was no difference in CLP group (P>0.05) in 6h, 12h, 24h after surgery.7 The level of IL-6 in serumAfter 6h, 12h and 24h of surgery, compared with sham and normal group, the level of serum IL-1 in CLP group was significant increased (P<0.05), there was no difference between sham group and normal group (P>0.05). Compared with 6h after surgery, the level was decreased in 24h (P<0.05).8 The level of TNF-αin serumAfter 6h, 12h and 24h of surgery, compared with sham and normal group, the level of TNF-αin CLP group was significant increased (P<0.05), there was no difference between sham group and normal group (P>0.05). Compared with 6h after surgery, the level was decreased in 24h (P<0.05).Conclusion:1 Our study successfully created a clinically relevant cecal ligation and puncture (CLP) model to mimic sepsis-induced AKI.2 The increase of the inflammation mediators in serum may a mechanism in sepsis-induced AKI.