The Study On The Mechanism Of Stearic Acid Activating NLRP3 Inflammasome Involved In Gouty Inflammation

Objective:To investigate the role of stearic acid activated NLRP3inflammasome in primary gouty arthritis and its clinical significance.Methods:The peripheral venous blood were collected sufficiently from A total of 15 patients with acute gout（AG group）,15 patients with intermittent gout（IG group）and 15 healthy controls（HC group）,heparin anticoagulation,divided into 4ml/tube,using PBS,0.1%Alcohol,C18:0（400μmol/L）,MSU（100μg/ml）,C18:0（400μmol/L）+MSU（100μg/ml）for stimulation respectively,It was incubated in a 37℃cell incubator containing5%CO ₂ for 6 hours,then the plasma was isolated and the peripheral blood mononuclear cells（PBMCs）were extracted.The expression of NLRP3,ASC,Caspase 1,IL-1βand GPR120 mRNA in PBMCs of AG,IG and HC groups were detected by real-time quantitative polymerase chain reaction（RT-qPCR）.The expression of plasma IL-1βprotein in patient with AG、IG group and HC group were measured by enzyme-linked immunosorbent assay（ELISA）.In addition,the above gout patients and healthy controls were collected for clinical data and laboratory indicators for comparative analysis.The data were analyzed by SPSS 19.0 statistical software,the data were compared between multiple groups with ANOVA（One-way ANOVA）,The least significant difference（LSD）was used for comparison among groups,the variables of different groups were analyzed with t-test or Rank transformation analysis,The results were expressed as mean±standard deviation,and the difference of P<0.05 was statistically significant.Results:（1）The indexes of white blood cell（WBC）,triglyceride（TG）,total cholesterol（TC）,creatinine（Crea）and uric acid（UA）in AG and IG groups were significantly higher than those in HC group（P<0.05,P<0.01）,and the indexes of neutrophils（GR）,high sensitive C reactive protein（hsCRP）in AG group were significantly higher than that of IG and HC group（P<0.01）,the index of erythrocyte sedimentation rate（ESR）in AG group was significantly higher than that in IG group（P<0.01）.（2）Peripheral venous blood of AG,IG and HC groups was stimulated by PBS,0.1%Alcohol,C18:0（400μmol/L）,MSU（100μg/ml）,C18:0（400μmol/L）+MSU（100μg/ml）.The expression of NLRP3 mRNA in PBMCs was significantly lower in AG and IG groups than that in HC group（P<0.01）,but there was no significant difference between AG group and IG group（P>0.05）;the expression of ASCmRNA,Caspase1mRNA,IL-1βmRNA,GPR120mRNA and IL-1βplasma protein in AG and IG groups was significantly higher than that in HC group（P<0.05,P<0.01）,and the expressions of ASCmRNA,Caspase1mRNA,GPR120mRNA and IL-1βplasma protein in AG group were significantly higher than those in HC group and IG group（P<0.05,P<0.01）,There was no significant difference of IL-1βmRNA between AG group and IG group（P>0.05）.（3）The expression of NLRP3 mRNA in PBMCs of AG、IG and HC groups stimulated with C18:0（400μmol/L）,MSU（100μg/ml）,C18:0（400μmol/L）+MSU（100μg/ml）were significantly lower than the control group（PBS group,0.1%Alcohol group）,the difference was statistically significant（P<0.05,P<0.01）;the expression of ASC,Caspase1,IL-1βand GPR120mRNA,IL-1βplasma protein were significantly higher than that of the stimulated control group（PBS group,0.1%Alcohol group）.（4）In the AG group,the expression of NLRP3mRNA in C18:0（400μmol/L）stimulation group was significantly higher than that in MSU（100μg/ml）stimulation group（P<0.05）,and C18:0（400μmol/L）+MSU（100μg/ml）stimulation group（P<0.01）.In the IG group,There were no significant difference in the expression of NLRP3 mRNA among in C18:0（400μmol/L）stimulation group、MSU（100μg/ml）stimulation group and C18:0（400μmol/L）+MSU（100μg/ml）stimulation group（P>0.05）.In the HC group,the expression of NLRP3 mRNA in C18:0（400μmol/L）stimulated group was significantly higher than that in C18:0（400μmol/L）+MSU（100μg/ml）stimulation group（P<0.01）;In the AG、IG and HC group,the expressions of ASC,Caspase1,IL-1βand GPR120mRNA,IL-1βplasma protein in C18:0（400μmol/L）stimulation group were significantly higher than those in MSU（100ug/ml）stimulation group（P<0.05,P<0.01）,which were significantly lower than those of C18:0（400μmol/L）+MSU（100μg/ml）stimulation group.Conclusion:In the process of inflammation development of gout,MSU crystals activation of NLRP3 inflammasome play an important role,Saturated long chain fatty acid C18:0（stearic acid）plays an important role in promoting gout inflammation,and its mechanism may be related to its activation NLRP3inflammasome and activation of its receptor GPR120 are closely related.