Objective To identify the effects of single immunoglobin IL-1 receptor related protein （SIGIRR） on inflammation induced by high mobility group box 1 （HMGB1） in A549 derived from human alveolar epithelial cells. Methods Eukaryotic expression vectors pCDNA3.1（+） constructed with SIGIRR cDNA were transiently transfected into A549 cells，in which SIGIRR was forced to be over-expressed. Western blot and RT-PCR were applied to detect the expression level of SIGIRR after transfection. After the stimulation by HMGB1，the transcriptional activity of NF-κB in A549 cells was detected by dual-luciferase reporter assay system，and the protein levels of inflammatory cytokine TNF-α and IL-1β were measured by ELISA. Results The expression level of SIGIRR increased significantly in A549 cells transfected with SIGIRR vectors. The transcriptional activity of NF-κB was enhanced obviously after HMGB1 treatment in A549 cells by dual-luciferase reporter assay system，while the transfection of SIGIRR vectors decreased the activity. The protein levels of TNF-α and IL-1β were down-regulated in A549 cells over-expressing SIGIRR after HMGB1 stimulation compared with the non-transfected cells. Conclusions Up-regulated SIGIRR expression can inhibit HMGB1-induced proinlammatory cytokine release in A549 cells such as TNF-α and IL-1β. The transcriptional activity of NF-κB is dampened by SIGIRR transfection，implying that the anti-inflammatory effects of SIGIRR may be involved in the regulation of NF-κB.
Objective To explore the secretion law of high mobility group box 1（HMGB1）in rat pancreatic acinar cells induced by trypsin activation peptide（TAP）and release of HMGB1 affected by ethyl pyruvate（EP）. Methods The experiment was performed in 12 SD rats. The pancreatic acinar cells of rats were taken out and then separated into three groups：control group， TAP group， and EP group. TAP was added into TAP group and EP group（keep TAP at a final concentration of 3 nmol/L）， respectively， but EP was added into EP group only （keep EP at a final concentration of 28 mmol/L）. The expressions of HMGB1 mRNA and protein were detected by using real-time quantitative reverse transcription polymerase chain reaction（RT-PCR）or Western blot at 3 h， 6 h， 12 h， and 24 h time point， respectively. The relationship between HMGB1 and TAP action time was explored by rank correlation. Results Compared with control group， the expressions of HMGB1 mRNA and protein were increased with prolongation of the TAP action in TAP group and EP group（P＜0.05）. Compared with TAP group， the expressions of HMGB1 mRNA and protein were decreased in EP group（P＜0.05）. The expressions of HMGB1 mRNA and protein were increased with prolongation of the TAP action（P＜0.05）， and were highest at 12 h time point（P＜0.01）in TAP group. There were positive correlation between the expressions of HMGB1 mRNA and protein and TAP action time（rs=0.971， P＜0.01；rs=0.966， P＜0.01）.Conclusions TAP can induce the release of HMGB1 in pancreatic acinar cells. There is positive relationship between TAP in early stage and HMGB1 in later period of acute pancreatitis. EP can inhibit the release of HMGB1.