Ulinastatin Reduces The Intestinal Inflammatory Response In Sepsis By Inhibiting The Activation Of NLRP3

Objective: To explore the damage of the intestinal mucosal barrier of septic rats by the activation of NOD-like receptor family,pyrin domain-containing 3(NLRP3)inflammasomes and the role of ulinastatin(UTI)on the expression of intestinal NF-κB/NLRP3 inflammasome signaling pathway in septic rats.Methods: According to the random number table method,64 male Wistar rats were divided into sham operation group(Sham group),sepsis group(CLP group),ulinastatin treatment group(UTI),and ulinastatin pretreatment group(pre-UTI)(the same dose of ulinastatin was given 1h before surgery),16 rats in each group.UTI group,100 k U/kg UTI was intraperitoneally injected 1,6,12 and 18 h after CLP operation.Pre-UTI group,100 k U/kg UTI was intraperitoneally injected 1 h before surgery,and UTI was injected at the corresponding time point.Observe and record the general conditions and survival of rats in each group.Hematoxylin-eosin(HE)staining for pathological scoring of rat ileum;serum tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),intestinal fatty acid binding protein(I-FABP)levels Measured by enzyme-linked immunosorbent assay(ELISA);Western blot test(Wertern Blot,WB)was used to detect the expression of nuclear transcription factor-κB p65,NLRP3,Caspase-1,ASC,and Claudin-1 in small intestine tissue;Intestinal tight junction protein-1(Claudin-1),occludin(Occludin)and inflammasome NLRP3,apoptosis-related speck protein(ASC),aspartate-specific cysteine protease 1(Caspase-1)expression by immunohistochemistry(IHC).Results: Compared with Sham group,24 h survival rate of CLP group was significantly decreased.The Chiu score of intestinal mucosa was significantly increased.The levels of I-FABP,IL-1βand TNF-α were significantly increased.The protein expressions of NF-κB p65,NLRP3,Caspase-1 and ASC in small intestine were significantly increased while the expression of Claudin-1 was significantly decreased by Western Blot.The expressions of Claudin-1 and Occludin decreased,and the expressions of NLRP3,Caspase-1 and ASC increased in the small intestinal tissues by IHC.Compared with the CLP group,after UTI intervention or UTI pretreatment,there was no significant difference in the 24 h survival rate(all P > 0.05),but intestinal tissue damage was significantly alleviated,specifically:Chiu score and plasma TNF-α,IL-The levels of 1β and I-FABP were significantly reduced(all P<0.05),and the expressions of NF-κB p65,NLRP3,Caspase-1,and ASC in the small intestine were significantly decreased(all P < 0.05).IHC indicated that the percentage of positive expression area(Area%)of Claudin-1 and Occludin in small intestine tissues was increased(all P < 0.05).The positive expression areas of NLRP3,Caspase-1 and ASC decreased(all P < 0.05).However,there was no statistically significant difference in the improvement between the UTI group and the UTI preconditioning group.Conclusion: Intestinal barrier dysfunction in sepsis may be related to the activation of NLRP3 inflammasomes in the intestinal mucosa;the protective effect of ulinastatin in the intestinal mucosa may be related to inhibiting the activation of NLRP3 inflammasomes in the intestinal mucosa,but pre-UTI group has no obvious advantage.