ABSTRACT
Objective To observe the damage of high mobility group box 1 (HMGB1) on human umbilical vein endothelial cell (HUVEC) barrier permeability and the protective effect of unfractionated heparin (UFH), and to explore the down-regulated protection effect mechanism of UFH on HMGB1-mediated vascular endothelial cadherin (VE-cadherin) expression. Methods The trypsin-digested HUVEC were subcultured in culture flasks. When the cells were grown to 80%, they were randomly divided into four groups: phosphate buffer (PBS) control group (200 μL PBS), recombinant human high mobility group box 1 (rhHMGB1) treatment group (100 μg/L rhHMGB1), UFH control group (10 kU/L UFH), and UFH pretreatment group (10 kU/L UFH+100 μg/L rhHMGB1). The cells in each group were challenged with different reagent for 24 hours, and the activity of endothelial cells was determined by methyl thiazolyl tetrazolium (MTT) colorimetric assay. The permeability of endothelial cells was measured by Transwell method, and the expression and distribution of VE-cadherin was observed by immunofluorescence. The protein expressions of VE-cadherin and phosphorylated p38 mitogen-activated protein kinase (p-p38MAPK) were determined by Western Blot. Results After treatment with 100 μg/L rhHMGB1 for 24 hours, the activity of endothelial cells was not significantly different from that of the PBS control group (A value: 0.230±0.004 vs. 0.255±0.006, P > 0.05), but the permeability was significantly increased (glucan FD40 fluorescence intensity: 11.05±0.12 vs. 6.34±0.39, P < 0.05). Compared with PBS control group, the fluorescence microscopy showed that the VE-cadherin membrane localization was reduced, the distribution was loose, and there were obvious fissures between cells in rhHMGB1 treatment group, and quantitative analysis showed the protein expression of VE-cadherin was decreased significantly (VE-cadherin/β-actin: 0.16±0.04 vs. 0.31±0.03, P < 0.05), and the expression of p-p38MAPK protein was significantly increased (p-p38MAPK/β-actin: 0.79±0.03 vs. 0.26±0.05, P < 0.05). UFH pretreatment could protect HMGB1-mediated endothelial cell injury, cell permeability was significantly reduced (glucan FD40 fluorescence intensity: 9.11±0.23 vs. 11.05±0.12), fluorescence expression of VE-cadherin was enhanced, membrane localization was significantly increased, quantitative analysis showed that VE-cadherin protein expression was significantly up-regulated (VE-cadherin/β-actin: 0.24±0.02 vs. 0.16±0.04), and p38MAPK phosphorylation level was significantly decreased (p-p38MAPK/β-actin: 0.54±0.05 vs. 0.79±0.03), the difference was statistically significant as compared with rhHMGB1 treatment group (all P < 0.05). There was no significant difference in all parameters between PBS control group and UFH control group. Conclusions UFH can protect the endothelial cell barrier from the HMGB1 by regulating the expression and distribution of VE-cadherin. The mechanism may be related to the inhibition of p38MAPK phosphorylation by UFH.
ABSTRACT
Objective To investigate the effect of high mobility group box-1 protein (HMGB1) on the permeability of human umbilical vein endothelial cells, and the protective effect of unfractionated heparin on HMGB1-mediated, endothelial cell tightly junction-related protein Claudin-5. Methods The human umbilical vein endothelial cells after trypsin digestion were subcultured in culture flasks and divided into 4 groups: blank control group (addition of PBS equivalent), rhHMGB1 treatment group (100 ng/mL), unfractionated heparin control group (UFH, 10 U/mL) and rhHMGB1+ unfractionated heparin-treated group (100 ng/mL rhHMGB1 + UFH 10 U/mL). After human umbilical vein endothelial cells were cultured: the viability of endothelial cells was determined by MTT assay; transwell method was used to measure the permeability of endothelial cells; the expression and distribution of Claudin-5 were determined by immunofluorescence; and Claudin-5 protein expression was detected by Western blotting. Results After treated with rhHMGB1 (100 ng/mL), the viability of endothelial cells was notsignificantly different from that of the blank control group (P> 0.05). After treated with rhHMGB1 (100 ng/mL) for 3 and 6 h respectively, the permeability of endothelial cells was not significantly different from that of the blank control group (P> 0.05). After 12 h and 24 h treatment of rhHMGB1, the permeability of endothelial cells was significantly increased compared with the blank control group (P< 0.05). However, after endothelial cells were incubated with unfractionated heparin and rhHMGB1 for 12 and 24 h, the permeability of endothelial cell was lower than that of rhHMGB1 treatment group (P< 0.05). Immunofluorescence and Western-blot showed that after treatment of rhHMGB1 for 24 h, the distribution and expression of claudin-5, a tightly junction-associated protein, was decreased. After incubation with unfractionated heparin and rhHMGB1, the expression of tightly junction-associated protein Claudin-5 was increased, as well as the fluorescence intensity of Claudin-5. Conclusions HMGB1 can increase the permeability of endothelial cells by mediating the abnormal distribution and decreased expression of Claudin-5. Unfractionated heparin can improve the expression and distribution of Claudin-5, improving the permeability of endothelial cells.
ABSTRACT
Objective To investigate the effect of unfractionated heparin (UFH) on the expression of heme oxygenase-1 (HO-1) in intestinal mucosa of mice with sepsis.Methods Thirty-six male C57BL/6J mice were randomly divided into sham group,cecal ligation and puncture (CLP) group and UHF group,n =12 in each group.Model of intestinal injury in sepsis was induced by CLP.In sham group,the mice were exposed without ligation of cecum.In UFH group,the mice were treated intravenously with 8 U of UFH via the tail vein half an hour before the operation and 12 hours after the surgery respectively.Six mice in each group were randomly chosen at 4 hours and 24 hours after operation to collect inferior vena venous blood samples and terminalileum tissues.The serum levels of interleukins (IL-1 β,IL-6),and tumor necrosis factor-α (TNF-α) were determined by enzyme linked immunosorbent assay (ELISA).The serum level of D-lactate was determined by colorimetry.Pathological changes of ileum tissue and Chiu score were observed after hematoxylin eosin (HE) staining.The HO-1 expression was detected immunohistochemically.Results In sham group,no significant changes in the serum levels of IL-1 β,IL-6,TNF-α and D-lactate were observed.Twenty-four hours after the operation,the structure of intestinal mucosa was basically normal without obvious pathology change and no HO-1 positive cells were found.The serum levels of IL-1 β,IL-6,TNF-α,and D-lactate in CLP group were gradually increased,and they were significantly increased as compared with sham group [IL-1 β (ng/L):40.87±2.88 vs.22.60±2.05 at 4 hours,113.73±3.96 vs.22.07±2.74 at 24 hours;IL-6 (ng/L):63.89±3.26 vs.44.89±3.38 at 4 hours,176.56±5.45 vs.45.76±4.02 at 24 hours;TNF-α (ng/L):194.62± 14.13 vs.152.05±6.22 at 4 hours,599.62± 10.20 vs.155.90± 14.18 at 24 hours;D-lactate (mmol/L):0.24± 0.02 vs.0.19 ± 0.01 at 4 hours,0.33 ± 0.04 vs.0.20 ± 0.02 at 24 hours,all P ＜ 0.05].Twenty-four hours after the operation,edema and inflammation in ileal mucosa,intestinal villi structural damage were observed,the Chiu score was significantly higher than those in the sham group [4.5 (3.0-5.0) vs.0 (0-1.0),P ＜ 0.05],and a small amount of HO-1 positive cells were localized in the intestinal mucosa.Compared with CLP group,the serum levels of IL-1 β,IL-6,TNF-α,and D-lactate of UFH group were significantly decreased [IL-1 β (ng/L):31.53 ± 2.90 vs.40.87 ± 2.88 at 4 hours,61.13 ± 2.80 vs.113.73 ± 3.96 at 24 hours;IL-6 (ng/L):51.16 ± 5.68 vs.63.89 ± 3.26 at 4 hours,81.16 ± 4.54 vs.176.56 ± 5.45 at 24 hours;TNF-α (ng/L):171.76± 5.60 vs.194.62± 14.13 at 4 hours,328.48 ± 10.79 vs.599.62± 10.20 at 24 hours;D-lactate (mmol/L):0.21 ±0.01 vs.0.24±0.02 at 4 hours,0.24±0.02 vs.0.33±0.04 at 24 hours,all P ＜ 0.05].Twenty-four hours after the operation,intestinal injury was ameliorated,the Chiu score was significantly lower [1.5 (1.0-5.0) vs.4.5 (3.0-5.0),P ＜ 0.05],and HO-1 positive cells in the intestinal mucosa was remarkably increased.Conclusion UFH can enhance the expression of HO-1 in intestinal mucosa,reduce the release of inflammatory factors,ameliorate the intestinal inflammatory response,and thus play a protective role in intestinal tissue in mice with sepsis.
ABSTRACT
ObjectiveTo approach the regulatory mechanism of high mobility group box-1 (HMGB1) on the expression of E-selectin in human umbilical vein endothelial cell (HUVEC).Methods Homeobox A9 (HOXA9) siRNA was transfected to HUVEC at logarithmic phase, real-time fluorescence quantitative polymerase chain reaction (real-time qPCR) and Western Blot were used to determine the HOXA9 mRNA expression and protein expressions; a blank control group and a nonsilence negative control group were set. HUVEC stable transfected with pRNA-u6.1/Neo-HMGB1 shRNA plasmids (HUVEC with low-expression HMGB1) was obtained, and HOXA9 and E-selectin mRNA expressions were determined with real-time qPCR; a nonsilence transfection group served as the negative control. The HOXA9 siRNA was transfected to HUVEC with low-expression HMGB1 as co-transfection group, and the E-selectin expressions was determined with real-time qPCR; a HMGB1 shRNA group and a HOXA9 nonsilence group served as control.Results① HOXA9 mRNA (2-ΔΔCT) and protein expression (integralA value) in blank control group were 1.094±0.115 and 1.031±0.060. Compared with nonsilence transfection group, HOXA9 siRNA transfection group could significantly reduced mRNA and protein expression of HOXA9 [HOXA9 mRNA (2-ΔΔCT): 0.257±0.030 vs. 1.035±0.091,t = 14.010,P = 0.002; HOXA9 protein (integralA value): 0.278±0.042 vs. 0.975±0.014,t = 27.310, P = 0.002].② Compared with nonsilence transfection group, HMGB1 shRNA transfection could up-regulate HOXA9 mRNA expression in HUVEC (2-ΔΔCT: 2.519±0.278 vs. 0.856±0.063,t = 10.100,P = 0.001), also could down-regulate E-selectin mRNA expression (0.311±0.046 vs. 1.080±0.201,t = 7.415,P = 0.000).③ Compared with HOXA9 nonsilence group and HMGB1 shRNA group, HMGB1 shRNA and HOXA9 siRNA co-transfected HUVEC cells could significantly elevate E-selectin mRNA expression (2-ΔΔCT: 3.445±0.428 vs. 1.085±0.212, 1.004±0.104,t1 = 8.507, t2 = 9.603, bothP< 0.001).Conclusion HMGB1 may regulate E-selectin expression through the HOXA9 regulation in HUVEC.
ABSTRACT
Objective To observe the effect of high mobility group box-1 protein (HMGB1) on the expression of intestinal epithelial tight junction protein occludin in murine severe acute pancreatitis (SAP).Methods Rat SAP model was estabilished by retrograde injection of 5 ％ sodium taurocholate into choledochopancreatic duct.Healthy wistar rats were divided randomly (random number) into three groups:control group,SAP group,pyrrolidine dithiocarbamate (PDTC) therapy group.Levels of plasm amylase,lipopolysaccharide (LPS) and D-lactate were determined.The changes of morphological damage of pancreasand intestinal tissues were observed by microscopy.The distribution and expression of occludin protein were observed by SP immunohistochemistry. The mRNA expression of HMGB1 in the intestinal mucosa was detected by reverse-transcription polymerase chain reaction (RT-PCR).The expressions of HMGB1 and occludin were determined by western blotting. One-way analysis of variance was performed with SPSS Windows 13.0 statistical analysis software,and a difference was accepted as significant if P ＜ 0.05.Results In comparison with the other two groups,levels of plasma LPS and D-lactate in SAP group increased markedly at 24 h after operation,which indicated that the penetrability of intestinal mucosal barrier increased (P ＜ 0.05 ). The expression of HMGB1 in the intestinal mucosa of SAP group increased significantly compared with control group (P ＜ 0.05).Whereas,the expression of occludin was significantly lower than control group (P ＜0.05).Compared with SAP group,the expression of HMGB1 was lower and the expression of occludin was higher in PDTC group ( P ＜ 0.05).Conclusions The over-expression of HMGB1 could down regulate the expression of occludin in intestinal tissues of SAP rats,and thus mediate an increase in penetrability of intestinal mucosal barrier.As PDTC inhibited the expression of HMGB1,the expression of occludin protein was up-regulated and the function of intestinal mucosal barrier was improved.
ABSTRACT
Objective To explore the effects of ethyl pyruvate (EP) on hepatic high mobility group box-1 protein (HMGB1) expression in experimental routine with acute necrotizing pancreatitis (ANT). Method ANP model was induced by retrograde injection of 5 % sodium taurocholate into pancreatic duct. Twenty-four male wistar rats were divided randomly into 3 groups(8 rats in each group): group A (ANT group); group B (ANP rats re-ceived ethyl pyruvate therapy) and group C (control group with sham operation). The concentration of plasma amylase (AMY), A.sr and ALT, and the activity of myeloperoxidase (MPO) in the liver were determined. The ex-pression of HMGB1 mRNA in liver was detected by using reverse transcription polymerase chain reaction (RT-PCR). The changes of morphological damage were observed under microscopy. The expression of HMGB1 in the liver was observed by using SP immunohistochemistry. ANOVA was performed with SPSS 10.0 statistical analysis software and the difference was accepted as significant if the P<0.05, as verified by using Duncan's and Tukey' s post hoc test. Results Compared with gxoup A,levels of plasma AMY,AST and ALT in group B were markedly lower (P<0.05). Compared with group C, MPO in group A was higher significantly (P<0.01).with group A, the pathological changes of pancreas and liver in group B were milder. Compared with group C,the hepatic HMGB1 mRNA expression was markedly higher in group A [(0.28±0.04) vs. (0.73±0.06), P<0.01]. By contrast,the HMGB1 mRNA expression was markedly lower in group B compared with group A [(0.46±0.05) vs. (0.73±0.06), P<0.05]. The HMGB1 protein expression in hepatocytes and Kupffer's cells of rats with ANP was significantly up-regulated compared with control group, but it was reduced significantly in EP treatment group. Conclusions HMGB1 as a late mediator in liver might be involved in the pathogenesis of acute hepatic injury with ANP. EP could down-regulate the hepatic HMGB1 expression together with improvement of liver function in rats with ANP.
ABSTRACT
Objective:To investigate the relationship between high mobility group box-1 protein (HMGB1) expression and gut mucosal barrier dysfunction during murine severe acute pancreatitis (SAP). Methods:Forty-eight male health adult Wistar rats were divided randomly into Control group and SAP groups. The concentration of plasma D-lactate and the activity of myeloperoxidase (MPO) in the intestinal tissue were determined. The expression of HMGB1 mRNA in intestinal mucosa was detected by reverse transcription polymerase chain reaction (RT-PCR) and the activity of HMGB1 was determined by Western blot. Results:Plasma D-lactate and MPO reached a peak level at 24h (16.41?4.65)?g/mL for Plasma D-lactate and(26.76?3.63)U/g for MPO respectively, (P
ABSTRACT
Objective To explore the effects of ethyl pyruvate (EP) on high mobility group box-1 protein (HMGB1) expression in severe acute pancreatitis (SAP) rats.Methods Ninety male wistar rats were divided randomly into three groups: Group A (SAP group); group B (SAP rats received ethyl pyruvate therapy); group C (control group). Specimens from rats in the three groups were taken at 3, 6, 12, 24 and 48 h after operation respectively. The concentration of plasma amylase and D-lactate the activity of malonyl dialdehyde (MAD) in the intestinal tissue were determined. The changes of morphological damage of intestinal tissue was observed by microscopy. The expression of HMGB1 in intestinal mucosa was observed by SP immunohistochemistry and the activity of HMGB1 was determined by western blot.Results Compared with group A, Ievels of plasma amylase, and D-lactate in group B decreased markedly (P