High Mobility Group Protein B1 mRNA Research Articles

HMGB1, TGF-β and NF-κB are associated with chronic allograft nephropathy.

The present study aimed to investigate the association between high mobility group protein B1 (HMGB1), transforming growth factor-β1 (TGF-β1), nuclear factor-κB (NF-κB) and chronic allograft nephropathy (CAN) and to identify the clinical significance of HMGB1, TGF-β1, NF-κB on patients with CAN. Between September 2012 and November 2014, 27 patients with CAN diagnosed by biopsy were enrolled in the present study and a further 30 patients that underwent nephrectomy following trauma were selected as the control group. Immunohistochemical staining with HMGB1, TGF-β1 and NF-κB expression in the renal tissues, and western blot analysis were used to measure the relative expression of HMGB1, TGF-β1 and NF-κB. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to estimate the relative expression of HMGB1, TGF-β1 and NF-κB mRNA. Statistical analysis was used to calculate the association between HMGB1, TGF-β1 and NF-κB expression and CAN grade. Immunohistochemical staining demonstrated that HMGB1, TGF-β1 and NF-κB had markedly positive expression rates in renal tubular epithelial cell cytoplasm and membranes in CAN renal tissues, and the positive rates of HMGB1, TGF-β1 and NF-κB increased with the aggravation of CAN pathological grade (I, II and III). The results of western blot analysis indicated that the expression levels of HMGB1, TGF-β1 and NF-κB were significantly higher in the CAN group, compared with the normal group (P<0.05), and the expression levels increased with the progression of CAN grade. A positive association among HMGB1, TGF-β1 and NF-κB expression was identified. RT-qPCR analysis demonstrated that the expression of HMGB1, TGF-β1 and NF-κB mRNA in the CAN group was significantly higher than in the normal group (P<0.05), and the relative expression level of HMGB1, TGF-β1 and NF-κB mRNA not only increased with the aggravation of CAN grade, but was also positively associated with the expression of HMGB1, TGF-β1 and NF-κB, respectively. The abnormal expression of HMGB1, TGF-β1 and NF-κB is therefore, an important manifestation of CAN and the expression of HMGB1, TGF-β1 and NF-κB mRNA in the renal tissues are significantly associated with CAN pathological progression. HMGB1, TGF-β1 and NF-κB may form a signaling pathway that leads to the occurrence of CAN, which induces renal interstitial fibrosis.

Glycyrrhizic acid exerts anti-inflammatory effect to improve cerebral vasospasm secondary to subarachnoid hemorrhage in a rat model

This study aimed to investigate the therapeutic effect of glycyrrhizic acid (GA) on the cerebral vasospasm (CVS) in a rat subarachnoid hemorrhage (SAH) model and to explore the potential mechanism. A total of 44 healthy male rats were randomly assigned into 3 groups: control group (n = 12), SAH group (n = 16) and GA group (n = 16). No treatment was conducted in control group; in SAH group and GA group, experimental CVS was induced using a double-hemorrhage model and then rats were intraperitoneally injected with normal saline and GA at 10 mg/kg, respectively, once daily. Three days later, neurological function was evaluated. Then, animals were sacrificed, and the basilar artery was collected. The inner diameter and vascular wall thickness were determined. Western blotting was employed to detect high mobility group protein B1 (HMGB1) protein expression and RT-PCR to detect the mRNA expression of IL-1β, IL-6, TNF-α, and IL-10 in the basilar artery. GA treatment significantly improved the neurological function following SAH. In GA group, the basilar artery diameter increased markedly and vascular wall thickness reduced significantly when compared with SAH group (p < 0.05). HMGB1 protein expression and mRNA expression of IL-1β, IL-6, TNF-α, and IL-10 in SAH group were significantly higher than in control group (p < 0.05). However, GA dramatically reduced IL-1β, IL-6, and TNF-α, and further elevated IL-10 expression as compared to SAH group (p < 0.05). GA may inhibit HMGB1 expression and subsequent production of inflammatory cytokines to prevent CVS following SAH.

Protective effect of controlled oxygen reperfusion on heart with cardiopulmonary bypass in dogs

Objective To observe the protective effects of controlled oxygen reperfusion (COR) on the hearts with cardiopulmonary bypass (CPB) and its possible mechanism. Methods Twelve canines were randomized into two groups: control group and test group. The CPB model was established. The animals in the control group received 80% fraction of inspired oxygen (FiO2) throughout the whole procedure. The animals in the test group received 40% FiO2 immediately at the declamping of aorta, and an additional 10% every 5 min later until 80% FiO2 was reached, and other procedures were the same as those in the control group. Arterial oxygen partial pressure (PaO2) was analyzed after anesthesia, before aortic declamping, 5, 10, 15, 20 and 25 min after aortic declamping, and at the end of the experiment. The blood samples were obtained after anesthesia (T1) and at the end of the experiment (T2), respectively. The animals were then sacrificed to obtain the left ventricle samples. The levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in plasma were measured by enzyme-linked-immunosorbent assay. The level of plasma cardiac troponin T (cTnT) was measured by ECL immunoassay system. The expression of high mobility group protein B1 (HMGB1) mRNA and protein in myocardial tissue was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. Results PaO2 was significantly lower in the test group than that in the control group at 5, 10, 15 and 20 min after aortic declamping (P=0.032, 0.021, 0.046, 0.013). The levels of IL-6, TNF-α and cTnT in plasma were low and there was no significant difference between the two groups at T1 (168.51±21.47 vs. 168.93±22.87; 72.19±2.11 vs. 76.21±6.50; 0.01 vs. 0.01). The levels of IL-6, TNF-α and cTnT in plasma increased from T1 to T2. The levels of IL-6, TNF-α and cTnT in the test group were lower than those in the control group (609.36±52.37 vs. 408.65±43.45; 255.09±10.15 vs. 174.09±8.65; 3.18±1.64 vs. 1.54±0.92). The difference was statistically significant (P=0.028, 0.034, 0.039). As compared with the control group, the expression of HMGB1 mRNA and HMGB1 protein was significantly down-regulated in the test group (P=0.026, 0.033). Conclusion The COR has the protective effects on the hearts with CPB, probably by down-regulating the HMGBI expression. Key words: Controlled oxygen reperfusion; Cardiopulmonary bypass; Interleukin-6; Tumor necrosis factor-α; High mobility group box 1

Regulatory effect of microRNA-141 on synthesis of high mobility group protein B1 in mouse carcinoma cell line hepal-6

To explore the regulatory effect of microRNA-141 (miR-141) on expression of high mobility group protein B1 (HMGB1) in mouse hepatoma carcinoma cell line (hepal-6 cells). The hepal-6 cells were divided into 4 groups: a miR-141 mimic group, a miR-141 mimic control group, a miR-141 inhibitor group and a miR-141 inhibitor control group. The miR-141 was transfected into hepal-6 cells with lipofectamine 2000. The levels of miR-141 and HMGB1 mRNA in the hepal-6 cells were detected by quantitative real-time PCR (qRT-PCR), and then HMGB1 protein was examined by Western blot. The regulatory effect of miR-141 on 3'-UTR of candidate target gene (HMGB1) was determined by dual-luciferase reporter assay. Compared with the control group, the level of miR-141 was up-regulated in the miR-141 mimic group, while down-regulated in the miR-141 inhibitor group. Moreover, the levels of HMGB1 mRNA and protein decreased in the miR-141 mimic group, while increased in the miR-141 inhibitor group. The dual-luciferase reporter assay showed that miR-141 could target the 3'-UTR of HMGB1 gene. MiR-141 can up-regulate the expression of HMGB1 protein at the post-transcriptional level by targeting to the specific sequence of 3'-UTR of HMGB1 gene, which suggests that HMGB1 gene may be a target gene of miR-141.

Expression and Significance of High-Mobility Group Protein B1 (HMGB1) and the Receptor for Advanced Glycation End-Product (RAGE) in Knee Osteoarthritis

BackgroundThis study was performed with the aim to explore the expression of high-mobility group protein B1 (HMGB1) and the receptor for advanced glycation end-product (RAGE) in knee osteoarthritis (KOA) and its clinical significance.Material/MethodsA total of 108 synovial tissues selected from KOA patients were included in the experimental group. Seventy-five synovial tissues of knee joints, selected from patients who were clinically and pathologically confirmed without joint lesion, were included in the control group. The mRNA and protein expressions of HMGB1 and RAGE were determined by using RT-PCR and immunohistochemistry, respectively. Western blotting was used for measuring relative protein expression. An ROC curve was drawn to evaluate the diagnostic value of HMGB1 and RAGE for KOA.ResultsThe positive cell number and positive expression intensity of HMGB1 and RAGE in synovial tissue was higher in the experimental group than in the control group. PI for HMGB1 and RAGE expression in KOA patients was positively correlated with clinical classification of X-ray films (P<0.05). HMGB1 and RAGE mRNA expressions, as well as relative protein expression of HMGB1 and RAGE in synovial tissue, were higher in the experimental group than in the control group (all P<0.05). The sensitivity of HMGB1 protein, RAGE protein, HMGB1 mRNA, and RAGE mRNA were 76.9%, 64.8%, 86.1%, and 64.8%, respectively; and the specificity was 100%, 96%, 74.7%, and 80%, respectively.ConclusionsThe protein and mRNA expressions of HMGB1 and RAGE are both increased in KOA patients, suggesting that they are involved in KOA.

Adiponectin Inhibits LPS-Induced HMGB1 Release through an AMP Kinase and Heme Oxygenase-1-Dependent Pathway in RAW 264 Macrophage Cells.

High mobility group protein B1 (HMGB1) is a late inflammatory mediator that exaggerates septic symptoms. Adiponectin, an adipokine, has potent anti-inflammatory properties. However, possible effects of adiponectin on lipopolysaccharide- (LPS-) induced HMGB1 release are unknown. The aim of this study was to investigate effects of full length adiponectin on HMGB1 release in LPS-stimulated RAW 264 macrophage cells. Treatment of the cells with LPS alone significantly induced HMGB1 release associated with HMGB1 translocation from the nucleus to the cytosol. However, prior treatment with adiponectin suppressed LPS-induced HMGB1 release and translocation. The anti-inflammatory cytokine interleukin- (IL-) 10 similarly suppressed LPS-induced HMGB1 release. Adiponectin treatment decreased toll-like receptor 4 (TLR4) mRNA expression and increased heme oxygenase- (HO-) 1 mRNA expression without inducing IL-10 mRNA, while IL-10 treatment decreased TLR2 and HMGB1 mRNA expression and increased the expression of IL-10 and HO-1 mRNA. Treatment with the HO-1 inhibitor ZnPP completely prevented the suppression of HMGB1 release by adiponectin but only partially inhibited that induced by IL-10. Treatment with compound C, an AMP kinase (AMPK) inhibitor, abolished the increase in HO-1 expression and the suppression of HMGB1 release mediated by adiponectin. In conclusion, our results indicate that adiponectin suppresses HMGB1 release by LPS through an AMPK-mediated and HO-1-dependent IL-10-independent pathway.

TNF-α induces the release of high mobility group protein B1 through p38 mitogen-activated protein kinase pathway in microglia

To determine the effect of p38 MAPK inhibitor (SB203580) on TNF-α -induced high mobility group protein B1 (HMGB1) expression in microglial cells. Microglial cells were treated with TNF-α (25 ng/mL, TNF-α group), TNF-α plus SB203580 (10 μmol/L, TNF-α+SB203580 group), SB203580 (SB203580 group) or serum-free medium (control group). After 16 h of incubation, the protein levels of p-p38 MAPK and HMGB1, and mRNA levels of HMGB1 were examined by ELISA, Western Blot and RT-PCR, respectively. There was a significant increase in p-p38 MAPK and HMGB1 levels in TNF-α-treated microglia cells (P<0.01). The TNF-α-induced HMGB1 protein and mRNA expression was suppressed by SB203580. TNF-α up-regulates HMGB1 expression in microglial cells through activation of the p38MAPK pathway.

High-mobility group protein B1 (HMGB1) and its potential in diagnosis and treatment of ovarian cancer

Objective: The objective of this research is to study the serum level of the high-mobility group protein B1 (HMGB1) in human ovarian tumor (OvCa) and in a healthy control. This study also aims to identify different HMGB1 levels before and after surgery and to explore the inhibitory effect of HMGB1 gene silencing in the proliferation and invasion ability of OvCa. Methods: Enzyme-linked immunosorbent assay was used to measure the serum level of HMGB1 in OvCa patients and healthy subjects. Lentivirus vector with HMGB1 shRNA was constructed and used to infect OvCa cells. The expressions of HMGB1 mRNA and protein were tested by real-time PCR and Western blot. Cell proliferation was detected using the Cell Counting Kit-8 assay, whereas cell invasion and migration were detected by Transwell assay. Results: The serum level of HMGB1 was more elevated in patients with malignant diseases compared with individuals with benign diseases and the control groups. In the malignant group, the serum level of HMGB1 decreased noticeably after therapy. Down-regulation of HMGB1 expression resulted in the inhibition of the biological behavior and metastasis of ovarian cancer cells. Conclusion: HMGB1 is closely associated with clinicopathologic features of OvCa. Knockdown of HMGB1 expression can significantly inhibit cell proliferation, cell migration, and cell invasion of OvCa. These findings indicate that HMGB1 can function as a therapeutic target for ovarian neoplasm in the future.

Hyperbaric Oxygen Alleviates Experimental (Spinal Cord) Injury by Downregulating HMGB1/NF-κB Expression

We presented an insight into the effect of hyperbaric oxygen (HBO) on spinal cord injury (SCI), aiming to uncover the dynamics of high-mobility group protein B1 (HMGB1) and nuclear factor κB (NF-κB) after HBO intervention in rats with acute SCI. Prognosis of SCI is directly linked with the control of secondary injury, in which the inflammatory response plays a leading role. HBO therapy can reduce this secondary damage to the spinal cord. We used an animal model to characterize the therapeutic effect of HBO on SCI. A growing number of studies have confirmed that HBO has gradually become an indispensable element after SCI in reducing neurological disorders, and improving the physical function and quality of life of patients. The role of HBO in the process of HMGB1/NF-κB-related secondary inflammatory responses in SCI has yet to be characterized. Rats were randomly categorized into sham, sham + HBO, SCI, and SCI + HBO groups. The expression levels of HMGB1 and NF-κB were measured at days 1, 3, 7, and 14 after SCI. After SCI, significant increases in mRNA and protein expression were observed for both HMGB1 and NF-κB (P< 0.01) compared with sham group. HMGB1 mRNA and protein expression levels were decreased after HBO intervention. The decreases were significant at days 7 and 14 (P< 0.05) post-HBO. In the SCI + HBO group, the significant decreases in NF-κB mRNA and protein expression levels were also observed at days 3, 7, and 14 (P< 0.05). After HBO intervention, a significant increase was seen in the Basso, Beattie, and Bresnahan score at days 7 and 14 (P< 0.05). HBO intervention may reduce the secondary damage of SCI caused by inflammatory responses via downregulating the expression of HMGB1/NF-κB, and promoting the repair of neurological function. N/A.

Increased Expression of High-Mobility Group Protein B1 in Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is an inflammation of the sinonasal mucosa and many inflammatory cells and cytokines are involved in its pathogenesis. High-mobility group protein B1 (HMGB1) is a DNA-binding protein that has a proinflammatory function when secreted into extracellular space. The purpose of this study was to evaluate the expression of HMGB1 in paranasal sinus mucosa and to determine the difference of HMGB1 expression between CRS patients and normal controls. Paranasal sinus mucosa was obtained from 10 patients with CRS and 10 patients without CRS. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR and Western blot analysis were performed to detect mRNA and protein. Sections of the mucosa were immunostained for localization of HMGB1 and image analysis was performed. RT-PCR and real-time PCR showed that the expression level of HMGB1 mRNA was significantly increased in the tissues of patients with CRS compared with controls. Western blot analysis showed that the expression level of HMGB1 protein was significantly increased in the tissues of CRS. In immunohistochemical staining, the HMGB1 protein was expressed in epithelial cells and inflammatory cells and the expression intensity of HMGB1 protein was stronger in CRS. HMGB1 is increased in the paranasal sinus mucosa of patients with CRS. These results suggest a possible contribution of HMGB1 in the pathophysiology of CRS.

Effects of rosiglitazone on pulmonary injury of septic rats induced by cecal ligation puncture

Objective To observe the effects of rosiglitazone,an agonist of peroxisome proliferator-activated receptor γ (PPARγ),on pulmonary injury in septic rats induced by cecal ligation puncture(CLP).Methods Eighty healthy male Wistar rats were randomly divided into 5 groups:sham group (group SHAM),cecal ligation puncture group (group CLP).rosiglitazone group (group ROSI),in which rats were intravenous injected with rosiglitazone 0.3 mg/kg 30 min before CLP.GW9662 group (group GW),in which rats were intravenous injected with GW9662 0.3 mg/kg 30 m in before CLP.GW9662 plus rosiglitazone group (group GW+ROSI),in which rats were injected intravenously with GW9662 0.3 mg/kg 30 min before CLP and then with rosiglitazone 0.3mg/kg 15 min before CLP.Eight rats were sacrificed at 6 and 24 h after CLP respectively in each group.Plasma was collected for the measurement of the level of plasma tumor necrosis factor-α (TNF-α) by enzyme linked immunosorbent assay (ELISA) and lung tissues were harvested for the detections of lung wet/dry (W/D) ratio,lung myeloperoxidase (MPO) activity,and lung tissue high mobility group protein B1 (HMGB1) mRNA expression by real-time PCR.Results The lung W/D ratio,MPO activity,plasma TNF-α level and the lung tissue HMGB1 mRNA expression of group CLP,group ROSI,group GW and group GW+ROSI were significantly higher than that of group SHAM.The lung W/D ratio,MPO activity,plasma TNF-α level and the lung tissue HMGB1 mRNA expression of group CLP [(5.31±0.14),(3.15±0.47) U/g,(15.064±0.448) μg/L and (0.758± 0.130)],group ROSI [(4.33±0.21),(2.21±0.31) U/g,(3.334±0.212) μg/L and (0.422±0.124)],group GW[(4.93±0.14),(3.13± 0.28) U/g,(15.001±0.343)μg/L and (0.732±0.198)] and group GW+ROSI[(4.87±0.13),(3.08±0.35) U/g,(14.866±0.412) μg/L and (0.763±0.017)] at 6 hafter CLP were significantly higher than that of the group SHAM[(3.98±0.17),(0.67±0.43) U/g,(0.452±0.033) μg/L and (0.244±0.053)](P＜0.05).At 24 h after CLP,the lung W/D ratio,MPO activity,plasma TNF-α level and the lung tissue HMGB1 mRNA expression of group CLP[(10.23±0.19),(3.61±-0.82) U/g,(1.542±0.193) μg/L and (2.413±0.211)],group ROS[(6.39±0.18),(2.17±1.02) U/g,(0.947±0.281) μg/L and (1.517±0.076)],group GW[(10.08±0.26),(3.45±0.36) U/g,(1.513±0.210).μg/L and (2.385±0.323)] and group GW+ROSI[(10.15±0.18),(3.53±0.32) U/g,(1.524±0.180) μg/L and (2.404±0.135)] were significantly higher than that of the group SHAM[(4.02±0.20),(0.68±0.34) U/g,(0.429±0.021) μg/L and (0.232±0.032)] (P＜0.05).The lung W/D ratio,MPO activity,plasma TNF-α level and the lung tissue HMGB1 mRNA expression of group ROSI were significantly lower than that of group CLP,group GW and group GW+ROSI respectively (P＜0.05).Conclusions Rosiglitazone can decrease the plasma TNF-α level and the lung tissue HMGB1 mRNA expression level and attenuate the pulmonary edema and inflammation in septic rats induced by CLP.It may have protective function against pulmonary injury. Key words: Sepsis; Pulmonary injury; Rosiglitazone

Effect of NF-κB inhibitor on high-mobility group protein B1 expression in a COPD rat model

The aim of the present study was to investigate the effect of the nuclear factor‑κB (NF‑κB) inhibitor, pyrrolidine dithiocarbamate (PDTC), on high‑mobility group protein B1 (HMGB1) expression in a rat model of chronic obstructive pulmonary disease (COPD). The COPD model was developed by administering lipopolysaccharides to the airways of rats and smudging (group B). In addition, a model of COPD complicated with hypoxia was established by administering lipopolysaccharides to the airways of rats, smudging and hypoxia (group C). PDTC was administered to the treatment groups by intraperitoneal injection. Reverse transcription polymerase chain reaction (RT‑PCR) and western blot analysis were used to detect the expression of HMGB1 and NF‑κB in lung tissue. RT‑PCR and western blot analysis demonstrated that HMGB1 mRNA and protein expression in groups B and C increased significantly (P<0.05) compared with control group A. In addition, HMGB1 expression in groups B and C gradually increased. HMGB1 mRNA and protein expression in groups B1 and C1 decreased (P<0.05) compared with B and C. NF‑κB protein expression in groups B and C increased significantly (P<0.05) compared with A. NF‑κB protein expression in groups B1 and C1 decreased compared with B and C. Therefore, HMGB1 mRNA and protein expression was identified to be positively correlated with NF‑κB protein expression. The NF‑κB inhibitor, PDTC, was demonstrated to significantly inhibit HMGB1 expression in lung tissues of rats with COPD and this mechanism may be associated with the NF‑κB signal transduction pathway.

LPS Induces HMGB1 Relocation and Release by Activating the NF-κB-CBP Signal Transduction Pathway in the Murine Macrophage-Like Cell Line RAW264.7

High mobility group protein B1 (HMGB1) is an important late inflammatory mediator in sepsis. Understanding the mechanisms that regulate HMGB1 release from cells and their downstream signal transduction pathways may lead to the ability to develop anti-HMGB1 therapies to treat inflammation. We stimulated murine macrophage-like RAW 264.7 cells with lipopolysaccharide (LPS) and LPS+ ethylpyruvate (EP) and examined the resulting HMGB1 expression and release. We also studied the expression of related signal transduction factors (NF-κB, p38 MAPK, and CBP). Gene expression of HMGB1 mRNA in RAW264.7 cell showed no significant change at 0-18 h after stimulation with LPS, but increased significantly at 24, 36, and 48 h. HMGB1 mRNA expression in the LPS+EP group was significantly lower than in LPS alone. HMGB1 was distributed mainly in the nucleus; the cytoplasmic level was low before LPS stimulation. After stimulation with LPS, cytoplasmic HMGB1 increased gradually and plateaued at a high level at 12-48 h. Nuclear HMGB1 decreased gradually at 12-24 h, then increased, maintaining a comparatively high level at 36-48 h. EP prevented this pattern significantly. LPS induced p38 MAPK activation and NF-κB signal pathways first, followed by CBP activation. Activated CBP acetylated HMGB1 was stored in a crino-lysosome and secreted activated NF-κB resulted in increased transcription and synthesis of HMGB1, but the expression of up-regulated HMGB1 mRNA was delayed. Extracellular HMGB1 originated from early synthetic reserves present in the nucleus. New HMGB1 protein was synthesized in the nucleus and transferred into the cytoplasm, causing an increase in HMGB1 in the nucleus and cytoplasm. EP inhibits HMGB1 mRNA up-regulation and release from LPS- stimulated macrophages. The molecular function of EP is to attenuate the activation p38 MAPK, NF-κB, and CBP signaling pathways.

The expression and implication of high mobility group protein B1 in the lung of the rats with sepsis

Objective To observe the dynamic changes of high mobility group protein B1 ( HMGB1 )expression in the lung of rats with Vibrio vulnificus sepsis so as to unravel the role of HMGB1 in lung injury.Methods Sixty rats of clean grade were randomly divided into normal control group ( A group, n = 10) and Vibrio vulnificus sepsis group (B group, n =50). Sepsis model was made in rats with subcutaneous injection of Vibrio vulnificus with concentration of 6 × 108 cfu/ml in dose of 0. 1 ml/100 g into left lower limb.The rats of group B were sacrificed 1 h, 6 h, 12 h, 24 h and 48 h after infection for taking lung tissues to detect the water content of lung and to observe the histopathological changes in lung under light microscope.The expression of HMGB1 mRNA and the level of HMGB1 protein in the lungs were detected by RT-PCR and Western blot, respectively. Data were analysed with ANOVA and LSD method for comparison between groups, and P ＜0.05 was considered statistically significant. Results Compared with the group A (0.652±0. 177), the expressions of HMGB1 mRNA in lung of rats of group B were significantly higher in 12 hours (1. 161 ±0.358, P=0.013), 24 hours (1.679 ±0.235, P =0.000) and 48 hours (1.258 ±0.274, P=0.004) and reached the peak in 24 h. Compared with group A (0.594 ±0. 190), the level of HMGB1 protein in rats of group B 6 h after infection ( 1. 408 ± 0. 567, P = 0. 026) was significantly increased (P＜0.05), and it reached peak in 24 h (2.415 ± 1.064, P =0.000) after infection. Compared with group A (0.699 ± 0.054), the lung water contents in rats of group B were significantly increased in 6 h (0.759±0.030, P=0.001), in 12 h (0.767 ±0.023, P =0.000), in 24 h (0.771 ±0.043, P=0.000) and in 48 h (0.789 ±0.137, P=0.000) after infection. Compared with group A, the pathological changes in the lung of rats in group B showed clearly marked pulmonary vascular congestion, interstitial edema and inflammatory cell infiltration, and those changes became more and more serious until alveolar sacs entirely collapsed and the boundaries of the alveolar septa could not be clearly identified in 48 h. Conclusions Vibrio vulnificus sepsis leads to the lung injury of infected rats, and the increase in the expression of HMGB1 mRNA in lung might be one of the mechanisms of lung injury in rats with Vibrio vulnificus sepsis. Key words: Vibrio vulnificus; Sepsis; Lung injury, High mobility group box1 protein ( HMGB1 ); Reverse transcription polymerase chain reaction(RT-PCR); Western blot; Lung water contents; Histopathology

Expression of high mobility group protein B1 in the lungs of rats with sepsis.

Vibrio vulnificus inside the body could activate the NF-κB signaling pathway and initiate the inflammatory cascade. The lung is one of the earliest organs affected by sepsis associated with acute lung injury. High mobility group protein B1 (HMGB1) is an important late-acting pro-inflammatory cytokine involving in the pathophysiology of sepsis. It is also involved in the injury process in the lung, liver and intestine. There has been no report on the involvement of HMGB1 in Vibrio vulnificus sepsis-induced lung injury. Sixty rats were randomly divided into a normal control group (group A, n=10) and a Vibrio vulnificus sepsis group (group B, n=50). Sepsis was induced in the rats by subcutaneous injection of Vibrio vulnificus (concentration 6×10(8) cfu/mL, volume 0.1 mL/100g)) into the left lower limbs. The rats in group B were sacrificed separately 1, 6, 12, 24, and 48 hours after the infection. Their lungs were stored as specimens, lung water content was measured, and lung pathology was observed under a light microscope. The expressions of the HMGB1 gene and protein in the lungs were detected by RT-PCR and Western blot. Data were analyzed with one-way analysis of variance (ANOVA) and the LSD method for pair-wise comparison between the two groups. P<0.05 was considered statistically significant. Compared to group A (0.652±0.177), HMGB1 mRNA expression in the lungs of group B was significantly higher at 0 hour (1.161±0.358, P=0.013), 24 hours (1.679±0.235, P=0.000), and 48 hours (1.258±0.274, P=0.004) (P<0.05), and peaked at 24 hours. Compared to group A (0.594±0.190), HMGB1 protein expression at 6 hours (1.408±0.567, P=0.026) after infection was significantly increased (P<0. 05), and peaked at 24 hours (2.415±1.064, P=0.000) after infection. Compared to group A (0.699±0.054), lung water content was significantly increased at 6 hours (0.759±0.030, P=0.001),12 hours (0.767±0.023, P=0.000), 24 hours (0.771±0.043, P=0.000) and 48 hours (0.789±0.137, P=0.000) after infection (P<0.05). Compared to group A, pathological changes at 12 hours in group B indicate marked pulmonary vascular congestion, interstitial edema and inflammatory infiltration. Alveolar cavity collapse and boundaries of the alveolar septum could not be clearly identified. Vibrio vulnificus sepsis can lead to injury in rat lungs, and increased HMGB1 expression in lung tissue may be one of the mechanisms for injury from Vibrio vulnificus sepsis.