Salidroside ameliorates sepsis-induced acute lung injury and mortality via downregulating NF-κB and HMGB1 pathways through the upregulation of SIRT1.

Sepsis is a life-threatening medical condition. Salidroside, a substance isolated from Rhodiola rosea, possesses antioxidant and anti-inflammatory properties. The effect and mechanism of salidroside on sepsis-induced acute lung injury still remains to be well clarified. Here, we investigated the effect and mechanism of salidroside on septic mouse models and explored the role of salidroside-upregulated SIRT1. Salidroside inhibited the inflammatory responses and HMGB1 productions in bacterial lipopolysaccharide (LPS)-treated macrophages and mice. Salidroside could also reverse the decreased SIRT1 protein expression in LPS-treated macrophages and mice. Salidroside also alleviated the sepsis-induced lung edema, lipid peroxidation, and histopathological changes and the mortality, and improved the lung PaO2/FiO2 ratio in cecal ligation and puncture (CLP)-induced septic mice. Salidroside significantly decreased the serum TNF-α, IL-6, NO, and HMGB1 productions, pulmonary inducible NO synthase (iNOS) and phosphorylated NF-κB-p65 protein expressions, and pulmonary HMGB1 nuclear translocation in CLP septic mice. Moreover, sepsis decreased the SIRT1 protein expression in the lungs of CLP septic mice. Salidroside significantly upregulated the SIRT1 expression and inhibited the inflammatory responses in CLP septic mouse lungs. These results suggest that salidroside protects against sepsis-induced acute lung injury and mortality, which might be through the SIRT1-mediated repression of NF-κB activation and HMGB1 nucleocytoplasmic translocation.

C/EBP homologous protein deficiency aggravates acute pancreatitis and associated lung injury.

AIM: To investigate the pathophysiological role of C/EBP homologous protein (CHOP) in severe acute pancreatitis and associated lung injury. METHODS: A severe acute pancreatitis model was induced with 6 injections of cerulein (Cn, 50 µg/kg) at 1-h intervals, then intraperitoneal injection of lipopolysaccharide (LPS, 7.5 mg/kg) in CHOP-deficient (Chop(-/-)) mice and wild-type (WT) mice. Animals were sacrificed under anesthesia, 3 h or 18 h after LPS injection. Serum amylase, lipase, and cytokines [interleukin (IL)-6 and tumor necrosis factor (TNF)-α], pathological changes, acute lung injury, and apoptosis in the pancreas were evaluated. Serum amylase and lipase activities were detected using a medical automatic chemical analyzer. Enzyme-linked immunosorbent assay kits were used to evaluate TNF-α and IL-6 levels in mouse serum and lung tissue homogenates. Apoptotic cells in sections of pancreatic tissues were determined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) analysis. The mouse carotid arteries were cannulated and arterial blood samples were collected for PaO2 analysis. The oxygenation index was expressed as PaO2/FiO2. RESULTS: Administration of Cn and LPS for 9 and 24 h induced severe acute pancreatitis in Chop(-/-) and WT mice. When comparing Chop(-/-) mice and WT mice, we observed that CHOP-deficient mice had greater increases in serum TNF-α (214.40 ± 19.52 pg/mL vs 150.40 ± 16.70 pg/mL; P = 0.037), amylase (4236.40 ± 646.32 U/L vs 2535.30 ± 81.83 U/L; P = 0.041), lipase (1678.20 ± 170.57 U/L vs 1046.21 ± 35.37 U/L; P = 0.008), and IL-6 (2054.44 ± 293.81 pg/mL vs 1316.10 ± 108.74 pg/mL; P = 0.046) than WT mice. The histopathological changes in the pancreases and lungs, decreased PaO2/FiO2 ratio, and increased TNF-α and IL-6 levels in the lungs were greater in Chop(-/-) mice than in WT mice (pancreas: Chop(-/-) vs WT mice, hemorrhage, P = 0.005; edema, P = 0.005; inflammatory cells infiltration, P = 0.005; total scores, P = 0.006; lung: hemorrhage, P = 0.017; edema, P = 0.017; congestion, P = 0.017; neutrophil infiltration, P = 0.005, total scores, P = 0.001; PaO2/FiO2 ratio: 393 ± 17.65 vs 453.8, P = 0.041; TNF-α: P = 0.043; IL-6, P = 0.040). Results from TUNEL analysis indicated increased acinar cell apoptosis in mice following the induction of acute pancreatitis. However, Chop(-/-) mice displayed significantly reduced pancreatic apoptosis compared with the WT mice (201.50 ± 31.43 vs 367.00 ± 47.88, P = 0.016). CONCLUSION: These results suggest that CHOP can exert protective effects against acute pancreatitis and limit the spread of inflammatory damage to the lungs.

Honokiol attenuates the severity of acute pancreatitis and associated lung injury via acceleration of acinar cell apoptosis.

Severe acute pancreatitis remains a life-threatening disease with a high mortality rate among a defined proportion of those affected. Apoptosis has been hypothesized to be a beneficial form of cell death in acute pancreatitis. Honokiol, a low-molecular-weight natural product, possesses the ability of anti-inflammation and apoptosis induction. Here, we investigate whether honokiol can ameliorate severe acute pancreatitis and the associated acute lung injury in a mouse model. Mice received six injections of cerulein at 1-h intervals, then given one intraperitoneal injection of bacterial lipopolysaccharide for the induction of severe acute pancreatitis. Moreover, mice were intraperitoneally given vehicle or honokiol 10 min after the first cerulein injection. Honokiol protected against the severity of acute pancreatitis in terms of increased serum amylase and lipase levels, pancreas pathological injury, and associated acute lung injury. Honokiol significantly reduced the increases in serum tumor necrosis factor-α, interleukin 1, and nitric oxide levels 3 h and serum high-mobility group box 1 24 h after acute pancreatitis induction. Honokiol also significantly decreased myeloperoxidase activities in the pancreas and the lungs. Endoplasmic reticulum stress-related molecules eIF2α (phosphorylated) and CHOP protein expressions, apoptosis, and caspase-3 activity were increased in the pancreas of mice with severe acute pancreatitis, which was unexpectedly enhanced by honokiol treatment. These results suggest that honokiol protects against acute pancreatitis and limits the spread of inflammatory damage to the lung in a severe acute pancreatitis mouse model. The acceleration of pancreatic cell apoptosis by honokiol may play a pivotal role.

Honokiol rescues sepsis-associated acute lung injury and lethality via the inhibition of oxidative stress and inflammation.

PURPOSE: Sepsis has a high mortality rate despite the recent advances in intensive care medicine and antibiotics. Honokiol, a low molecular weight natural product, is known to possess anti-inflammatory activity. Here, we investigate whether honokiol can ameliorate acute lung injury and lethal response in murine models of sepsis. METHODS: Mice were intraperitoneally given vehicle or honokiol 30 min after the induction of sepsis by cecal ligation and puncture (CLP) and endotoxemia by administration of E. coli lipopolysaccharide (LPS). RESULTS: The productions of serum tumor necrosis factor-α (TNF-α), nitric oxide (NO), and high mobility group box 1 (HMGB 1) were increased in mice during sepsis, which could be reversed by honokiol. Honokiol could also effectively reduce the increased blood lipid peroxidation and nitrotyrosine in septic mice. Honokiol significantly reversed the inductions of inducible NO synthase and nuclear factor-κB (NF-κB) activation in the lungs of mice during sepsis. Honokiol also effectively rescued the lung edema, lung pathological changes, and lethality in septic mice. CONCLUSIONS: These findings suggest that honokiol is capable of suppressing the lethal response and acute lung injury associated with sepsis, and support the potential use of honokiol as a therapeutic agent for the conditions associated with septic shock.

Uropathogenic Escherichia coli-induced inflammation alters mouse urinary bladder contraction via an interleukin-6-activated inducible nitric oxide synthase-related pathway.

Escherichia coli is the most common cause of urinary tract infection. Elevated blood and urine interleukin-6 (IL-6) levels have been shown in inflammatory urinary tract diseases. The role of IL-6 in mediating the urodynamic dysfunction in response to E. coli-induced urinary tract infection has not yet been fully elucidated. In this study, we investigated the role of IL-6 in the nitric oxide (NO)-triggered alteration of contractile responses in the urinary bladder under an E. coli-induced inflammatory condition. The electrical field stimulation (EFS)-evoked contractions of the isolated detrusor strips, and immunoblotting for detecting protein expression in the bladders was measured short term (1 h) or long term (6 or 24 h) after intraperitoneal injection of E. coli endotoxin (lipopolysaccharide [LPS]) or intravesical instillation of human pyelonephritogenic E. coli-J96 (O4:K6) strain or LPS into mice. IL-6 and NO productions were increased in the urinary bladders of mice 1 to 24 h after LPS or E. coli-J96 treatment. Inducible NO synthase (iNOS) expression and protein kinase C (PKC) activation and EFS-evoked detrusor contractions were increased in the bladders at 6 h after LPS or E. coli-J96 treatment, which could be reversed by anti-IL-6 antibody and iNOS inhibitor aminoguanidine. At 1 h after LPS administration, bladder NO generation, endothelial NOS expression, and EFS-evoked detrusor contractions were effectively increased, whereas anti-IL-6 antibody could not reverse these LPS-induced responses. These results indicate that IL-6 may play an important role in the iNOS/NO-triggered PKC-activated contractile response in urinary bladder during E. coli or LPS-induced inflammation.

Uropathogenic Escherichia coli alters muscle contractions in rat urinary bladder via a nitric oxide synthase-related signaling pathway.

BACKGROUND: Uropathogenic Escherichia coli (UPEC) is a common cause of urinary-tract infection. The mechanisms by which bacteria cause the symptoms of cystitis remain unclear. METHODS: The contractions of isolated rat detrusor strips evoked by electrical field stimulations (EFS) or by exogenous agonists and immunoblotting for the detection of protein expression in the bladder were measured in the short (1 h) and long (24 h) term after the intravesical instillation of J96 (O4:K6) strain or UPEC isolated from patients with acute E. coli pyelonephritis or E. coli lipopolysaccharide (LPS). RESULTS: One hour after the instillation of UPEC, the level of endothelial nitric oxide synthase (eNOS) and the contractile response, but not protein kinase C (PKC) and extracellular signal-regulated kinase (ERK)-1/2 activation, were higher. Twenty-four hours after UPEC treatment, detrusor contractions were decreased, and inducible (i) NOS protein expression and ERK1/2 phosphorylation, but not PKC activation, were observed. Both aminoguanidine and PD98059 treatment markedly reversed the decrease of EFS- and acetylcholine-evoked detrusor contractions induced by UPEC. The instillation of LPS triggered PKC activation but not ERK1/2 phosphorylation. CONCLUSIONS: Short-term intravesical instillation of UPEC enhances detrusor contractions through an eNOS-related pathway, but iNOS-regulated ERK1/2 signaling may be involved in long-term UPEC treatment-induced responses. There are different mechanisms involved in the responses induced by UPEC and LPS.