Analysis Of The Relationship Between Differential Expression Of Exosome MiRNAs And Sepsis-associated Encephalopathy In Rats

Background Sepsis-associated encephalopathy(SAE),a diffuse cerebral dysfunction in the absence of direct CNS infection,is associated with increased mortality and morbidity rates in patients with sepsis.Exosomes are endosomal-derived phospholipid bilayer vesicles that are 40–160 nm(on average 100 nm)in diameter.Micro RNA(mi RNA)is a type of small endogenous RNA with a length of about 20-24 nucleotides,with various critical regulatory effects in cells.Some studies have suggested that mi RNAs can be found in exosomes and serve as diagnostic biomarkers for many diseases.Compared with mi RNAs found directly in the blood,exosomes better prevent the degradation of mi RNAs,making them more valuable biomarkers.Exosomes have been extensively studied in various diseases but rarely in SAE.Objective In this study,brain tissue-derived exosomes of sepsis-associated encephalopathy were identified by high-throughput sequencing atlas,and differential expression exosomal mi RNAs between brain tissue,cerebrospinal fluid,and plasma were analyzed to explore the correlation between exosomal mi RNAs and SAE.Method The SAE model was constructed by intraperitoneal injection of lipopolysaccharide.The SAE model was successfully constructed by neurobehavioral scores,HE staining of brain tissue,and Evans blue staining.Twenty-six SD rats were randomly divided into a control group and an SAE group,with 13 rats in each group,among which three rats in each group were used for brain-derived exosomal mi RNAs high-throughput sequencing,and ten rats were selected for verification experiments.Exosomes were extracted by brain tissue section and super centrifugation method,and differential expression exosomal mi RNAs from brain tissue,cerebrospinal fluid,and plasma were verified by q RT-PCR.The measurement data were described using Mean±SD.If the variance was homogeneous,the t-test of two independent samples was used for comparison between the two groups.The Mann-Whitney U test was applied if the normality and variance homogeneity were unmet.The correlations were tested by Spearman correlation analysis,using P<0.05 was considered statistically significant.Result One hundred one differentially expressed mi RNAs were identified by high-throughput sequencing of brain tissue-derived exosomes between SAE and control groups.Of these,16 were significantly down-regulated,and 85 were significantly up-regulated.Four exosomal mi RNAs(namely mi R-127-3p,mi R-423-3p,mi R-378 b,and mi R-106-3p)were screened out according to the function of target genes and differential expression ratio.Further,q RT-PCR verification revealed significant differences in four mi RNAs in SAE brain tissue,cerebrospinal fluid,and plasma exosomes compared with the control group(p < 0.0001).Further analysis showed a high correlation between plasma,cerebrospinal fluid,and brain tissue-derived exosomal mi RNAs(p < 0.001).Conclusions In this study,through comprehensive analysis and verification of brain tissue-derived exosomal mi RNAs expression profiles in SAE,we found that exosomal mi R-127-3p,mi R-423-3p,mi R-378 b,and mi R-106-3p have significant correlation with the occurrence of SAE.