Objective To study the expression of CD163 in macrophages and sCD163 level in the serum of neonatal rat model of Escherichia coli (E. coli) sepsis. Methods A total of 72 specific-pathogen-free (SPF) neonatal rats (P7) were randomly and equally assigned into experiment group and control group. E. coli was injected peritoneally and the sepsis model was established in the experiential group while normal saline (NS) was injected in the control group. Samples were collected at 2, 4, 6, 12, 24 h and 48 h after the treatment. CD163 expression in macrophages of lung and liver tissues were tested using immunohistochemical(IHC) method, and the dynamic changes of sCD163 concentration in the serum were monitored usingenzyme-linked immunosorbent assay (ELISA) method. Results In the experiment group, CD163 expression in macrophages of lung and liver were gradually decreased at eachtime point (P <0. 001). At 2 h, CD163 expression in macrophages showed no significant differences between the two groups (P >0. 05). At 4 h and later timepoints, the differences were statistically significant (P <0. 001) . Meanwhile, sCD163 in the serum increased gradually (P <0. 01). At 2 h, sCD163 in the serum showed no significant differences between the two groups (P >0. 05). At 4 h and later timepoints, the differences were statistically significant (P <0. 001). Conclusions CD163 plays an important role in sepsis.

Objective: To investigate the effect of bilirubin on inflammatory signaling pathway mediated by NOD-like receptor 2(NOD2) in premature infants. Methods: Fifteen cases of premature infants hospitalized at the Department of Neonatology, Children′s Hospital of Soochow University from April 2016 to January 2017, were selected, and 2 mL peripheral blood were collected from 15 cases of premature infants, and the mononuclear cells were isolated and divided into 6 groups, including blank control group (group A), muramyl dipeptide(MDP) group (group B), 102 μmol/L bilirubin group(group C), 102 μmol/L bilirubin+ MDP group (group D), 153 μmol/L bilirubin+ MDP group (group E), 255 μmol/L bilirubin+ MDP group (group F). Group A and group B were stimulated by buffer, group C, group D, group E and group F were stimulated by 102 μmol/L, 102 μmol/L, 153 μmol/L, 255 μmol/L bilirubin, respectively.The supernatant was discarded after 1 h, then the medium was added to group A and group C, and the rest of the 4 groups were agonisted with MDP, the cells were stimulated for 24 h, and then the cells and supernatant fluids were collected respectively, the expression levels of NOD2 mRNA in the cells were determinated by real time-PCR, and the expression levels interleukin-6(IL-6) and tumor necrosis factor-α(TNF-α) in the supernatant was determinated by enzyme linked immunosorbent assay. Results: The expression levels of NOD2 mRNA had no obvious changes after being stimulated by MDP or by different concentrations of bilirubin(7.16±3.08, 6.19±1.99, 7.02±4.04, 6.84±1.81) compared to those of the blank control group(7.46±3.70)(all P>0.05). After being stimulated by MDP, the expression level of IL-6 (5.13±2.36)was significantly higher than that of the blank control group(3.84±1.44), and the difference was statistically significant(P<0.05), but TNF-α had no obvious changes(4.85±2.47 vs.4.04±2.26, P>0.05). The expression levels of IL-6 and TNF-α had no obvious changes compared to those of the blank control group after being stimulated by 102 μmol/L bilirubin(3.26±1.06 vs.3.84±1.44, 3.45±1.84 vs.4.04±2.26, all P>0.05); but the expression levels of IL-6 and TNF-α were significantly lower after 153 μmol/L and 255 μmol/L bilirubin stimulation (IL-6: 2.58±1.33, 2.16±0.94; TNF-α: 2.32±1.49, 2.42±1.42)compared to those of the blank control group(3.84±1.44, 4.04±2.26), and the differences were statistically significant(all P<0.05). Conclusions Bilirubin have no obvious inhibitory effect on NOD2, and low concentration of bilirubin had no obvious inhibitory effect on IL-6 or TNF-α in this study, but high concentration of bilirubin can inhibit the expression levels of IL-6 and TNF-α, hyperbilirubin may inhibit the ability of anti-infection immune response in body by inhibiting inflammatory signaling pathway mediated by NOD2.

Objective:To study the expression and significance of neutrophil extracellular traps (NETs) in neonatal sepsis.Methods:Prospective research were used in this study. Term infants with neonatal sepsis hospitalized for the first time in the Department of Neonatology, Children's Hospital of Soochow University from June 2020 to November 2020 were selected as the sepsis group. According to a ratio of about 1∶1, term infants with mild hyperbilirubinemia who were admitted in the same period, with gestational age difference less than 1 week from those in the sepsis group, and whose parents agreed to participate in the study were selected as the control group. On admission, clinical data as well as blood samples of the two groups were collected. Levels of NETs marker citrulline histone H3-DNA (CitH3-DNA) were detected by Enzyme-linked immunosorbent assay, and circulating cell-free DNA (cfDNA) was tested by the fluorescence microplate reader. General data, white blood cell (WBC), neutrophil count (NE), platelet (PLT), C- reactive protein (CRP), blood culture, CitH3-DNA and cfDNA were compared between the two groups. The diagnostic value of CITH3-DNA and cfDNA in neonatal septicemia was analyzed by the receiver operating characteristic (ROC) curve.Results:A total of 74 infants were included in the study, including 39 cases in the sepsis group and 35 cases in the control group. CitH3-DNA and cfDNA in the sepsis group were significantly higher than those in the control group [CitH3-DNA (optical density): 0.85±0.05 vs. 0.48±0.03, cfDNA (mg/L): 0.90±0.05 vs. 0.56±0.03] ( P<0.01). There was no significant correlation between CitH3-DNA and cfDNA. The level of CitH3-DNA had no correlation with gender, gestational age, age, birth weight, WBC, NE, PLT and CRP ( P>0.05). cfDNA was positively correlated with age and NE ( P<0.05), and negatively correlated with PLT ( P<0.05). Combined with CRP, the area under the ROC curve of CitH3-DNA+CRP, cfDNA+CRP, and CitH3-DNA+cfDNA+CRP were 0.947, 0.947 and 0.970 respectively, and the sensitivity to predict neonatal sepsis were 92.3%, 84.6% and 94.9% respectively, the specificity were 94.3%, 97.1% and 100% respectively, all higher than the predictive value of each index alone. Conclusions:The plasma NETs levels increase significantly in neonatal sepsis patients, especially CitH3-DNA with a strong specificity, and can be considered as a biomarker for early diagnosis of neonatal sepsis. NETs together with CRP, could drastically improve the predictive value of neonatal sepsis.