Relationship between SAA and sepsis and its biological significance

Objective To study the biomarkers related to sepsis quantitatively and qualitatively with a CLP mice model and proteomic analysis. Methods 85 mice were divided into model group and sham operation group to make a model of CLP sepsis in mice, to observe the natural process of the development of sepsis. At the same time, iTRAQ method was used to detect and identify the serum protein at the critical time point. The key molecules closely related to the process of sepsis were determined, and the expression of mRNA in different tissues was observed by qPCR method. Results The survival curve showed that 12 - 32 h of sepsis mice was the key time of death, and then went into the natural recovery period. At the same time, a group of proteins were found to match the process in appearance, peak and recovery time. Protein identification confirmed that the proteins included SAA1 and SAA2, and the expression levels were equal. Examination of SAA1 mRNA expression in different tissues revealed that the liver was the main site for the synthesis of SAA1, but extrahepatic tissue was the source of the so-called acute phase response protein SAA1. Conclusions SAA may have a variety of biological functions. The serum SAA detected by conventional methods is a mixture of SAA1 and SAA2, and the extrahepatic tissue is the main source of detected serum SAA, which can be used as a biomarker for sepsis. SAA synthesized in the liver is transported through specific pathways and may be involved in the rehabilitation of sepsis. Key words: Sepsis; iTRAQ; Serum amyloid A1; Cecal ligation and puncture