Influence of dexamethasone on the expression levels of P-selectin protein in multiple organs of rats with severe acute pancreatitis

Effect of emodin on acute lung injury: a meta-analysis of preclinical trials

BACKGROUND

Emodin has protective effects on acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). This meta-analysis intended to illustrate the efficacy of emodin on ALI/ARDS animal models.

METHODS

Relevant preclinical studies were searched on PubMed, EMBASE, and Web of Science. Standardized mean differences (SMDs) with corresponding confidence intervals (CIs) were used to compare lung injury scores, lung wet-to-dry weight ratios (W/D), myeloperoxidase (MPO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, IL-18, PaO2, and PaCO2 between the treatment and control groups. The article quality was appraised using the SYRCLE tool.

RESULTS

Twenty one studies published between 2014 and 2023 were enrolled. Compared with the control group, emodin significantly reduced lung injury scores (SMD: -3.63; 95% CI: -4.36, -2.90; p < 0.00001), W/D ratios (SMD: -3.23; 95% CI: -4.29, -2.16; p < 0.00001), and MPO levels (SMD: -2.96; 95% CI: -3.92, -1.99; p < 0.00001). Furthermore, emodin downregulated TNF-α (SMD: -3.04; 95% CI: -3.62, -2.47; p < 0.00001), IL-1β (SMD: -3.76; 95% CI: -4.65, -2.87; p < 0.00001), IL-6 (SMD: -3.19; 95% CI: -3.95, -2.43; p < 0.00001), and IL-18 levels (SMD: -4.83; 95% CI: -6.10, -3.57; p < 0.00001). Emodin improved gas exchange dysfunction, increased PaO2 (SMD: 3.76; 95% CI: 2.41, 5.11; p < 0.00001), and decreased PaCO2 (SMD: -3.83; 95% CI: -4.90, -2.76; p < 0.00001). Sensitivity analyses and stratified analyses were conducted for outcome measures with heterogeneity.

CONCLUSIONS

Emodin treatment can effectively reduce the severity of ALI in animal models. Additional animal investigations and clinical trials involving human subjects are imperative.

Emodin Protects Against Acute Pancreatitis-Associated Lung Injury by Inhibiting NLPR3 Inflammasome Activation via Nrf2/HO-1 Signaling

Aim

Lung injury is a common complication of acute pancreatitis (AP), which leads to the development of acute respiratory distress syndrome and causes high mortality. In the present study, we investigated the therapeutic effect of emodin on AP-induced lung injury and explored the molecular mechanisms involved.

Materials and Methods

Thirty male Sprague-Dawley rats were randomly divided into AP (n=24) and normal (n=6) groups. Rats in the AP group received a retrograde injection of 5% sodium taurocholate into the biliary-pancreatic duct and then randomly assigned to untreated, emodin, combined emodin and ML385, and dexamethasone (DEX) groups. Pancreatic and pulmonary injury was assessed using H&E staining. In in vitro study, rat alveolar epithelial cell line L2 cells were exposed to lipopolysaccharide and treated with emodin. Nrf2 siRNA pool was applied for the knockdown of Nrf2. The contents of the pro-inflammatory cytokines in the bronchoalveolar lavage fluid and lung were determined using enzyme-linked immunosorbent assay. The expressions of related mRNAs and proteins in the lung or L2 cells were detected using real-time polymerase chain reaction, Western blot, immunohistochemistry and immunofluorescence.

Key Findings

Emodin administration alleviated pancreatic and pulmonary injury of rats with AP. Emodin administration suppressed the production of proinflammatory cytokines, downregulated NLRP3, ASC and caspase-1 expressions and inhibited NF-κB nuclear accumulation in the lung. In addition, Emodin increased Nrf2 nuclear translocation and upregulated HO-1 expression. Moreover, the anti-inflammatory effect of emodin was blocked by Nrf2 inhibitor ML385.

Conclusion

Emodin effectively protects rats against AP-associated lung injury by inhibiting NLRP3 inflammasome activation via Nrf2/HO-1 signaling.

Emodin alleviates severe acute pancreatitis-associated acute lung injury by decreasing pre-B-cell colony-enhancing factor expression and promoting polymorphonuclear neutrophil apoptosis

The present study aimed to evaluate the protective effects of emodin on severe acute pancreatitis (SAP)‑associated acute lung injury (ALI), and investigated the possible mechanism involved. SAP was induced in Sprague‑Dawley rats by retrograde infusion of 5% sodium taurocholate (1 ml/kg), after which, rats were divided into various groups and were administered emodin, FK866 [a competitive inhibitor of pre‑B‑cell colony‑enhancing factor (PBEF)] or dexamethasone (DEX). DEX was used as a positive control. Subsequently, PBEF expression was detected in polymorphonuclear neutrophils (PMNs) isolated from rat peripheral blood by reverse transcription‑quantitative polymerase chain reaction and western blotting. In addition, histological alterations, apoptosis in lung/pancreatic tissues, apoptosis of peripheral blood PMNs and alterations in the expression of apoptosis‑associated proteins were examined by hematoxylin and eosin staining, terminal deoxynucleotidyl‑transferase‑mediated dUTP nick end labeling assay, Annexin V/propidium iodide (PI) assay and western blotting, respectively. Serum amylase activity and wet/dry (W/D) weight ratios were also measured. An in vitro study was also conducted, in which PMNs were obtained from normal Sprague‑Dawley rats and were incubated with emodin, FK866 or DEX in the presence of lipopolysaccharide (LPS). Apoptosis of PMNs and the expression levels of apoptosis‑associated proteins were examined in cultured PMNs in vitro by Annexin V/PI assay and western blotting, respectively. The results demonstrated that emodin, FK866 and DEX significantly downregulated PBEF expression in peripheral blood PMNs. In addition, emodin, FK866 and DEX reduced serum amylase activity, decreased lung and pancreas W/D weight ratios, alleviated lung and pancreatic injuries, and promoted PMN apoptosis by regulating the expression of apoptosis‑associated proteins: Fas, Fas ligand, B‑cell lymphoma (Bcl)‑2‑associated X protein, cleaved caspase‑3 and Bcl‑extra‑large. In addition, the in vitro study demonstrated that emodin, FK866 and DEX significantly reversed the LPS‑induced decrease of apoptosis in PMNs by regulating the expression of apoptosis‑associated proteins. In conclusion, the present study demonstrated that emodin may protect against SAP‑associated ALI by decreasing PBEF expression, and promoting PMN apoptosis via the mitochondrial and death receptor apoptotic pathways.

Thalidomide Inhibits Adhesion Molecules in Experimental Acute Pancreatitis-Associated Lung Injury

Preclinical Research The study evaluated the effect of thalidomide on adhesion molecule expression in acute pancreatitis-associated lung injury in rats. Acute pancreatitis was induced in rats by retrograde infusion of 5% sodium taurocholate into the bile-pancreatic duct, and thalidomide (100 mg/kg) was given daily by intragastric route for 8 days before this treatment. Serum lipase (LPS), protein levels in bronchoalveolar lavage fluid (BALF), superoxide dismutase (SOD), glutathione peroxidase (GSHpx), and malondialdehyde (MDA) levels in lung were measured. Compared with the acute pancreatitis- group, lung histopathology, serum LPS, protein levels in BALF, SOD, GSHpx, and MDA levels, and the expression levels of intercellular adhesion molecule-1 and E-selectin mRNA and protein in rats given thalidomide were improved (P < 0.01). Thus, thalidomide may reduce the expression of adhesion molecules via inhibition of oxidative stress to alleviate acute pancreatitis-associated lung injury in a rat model. Drug Dev Res, 2014. © 2014 Wiley Periodicals, Inc.

Dexamethasone blocks the systemic inflammation of alveolar hypoxia at several sites in the inflammatory cascade

Alveolar hypoxia produces a rapid and widespread systemic inflammation in rats. The inflammation is initiated by the release into the circulation of monocyte chemoattractant protein-1 (MCP-1) from alveolar macrophages (AMO) activated by the low alveolar Po(2). Circulating MCP-1 induces mast cell (MC) degranulation with renin release and activation of the local renin-angiotensin system, leading to microvascular leukocyte recruitment and increased vascular permeability. We investigated the effect of dexamethasone, a synthetic anti-inflammatory glucocorticoid, on the development of the systemic inflammation of alveolar hypoxia and its site(s) of action in the inflammatory cascade. The inflammatory steps investigated were the activation of primary cultures of AMO by hypoxia, the degranulation of MCs by MCP-1 in the mesentery microcirculation of rats, and the effect of angiotensin II (ANG II) on the leukocyte/endothelial interface of the mesentery microcirculation. Dexamethasone prevented the mesentery inflammation in conscious rats breathing 10% O(2) for 4 h by acting in all key steps of the inflammatory cascade. Dexamethasone: 1) blocked the hypoxia-induced AMO activation and the release of MCP-1 and abolished the increase in plasma MCP-1 of conscious, hypoxic rats; 2) prevented the MCP-1-induced degranulation of mesentery perivascular MCs and reduced the number of peritoneal MCs, and 3) blocked the leukocyte-endothelial adherence and the extravasation of albumin induced by topical ANG II in the mesentery. The effect at each site was sufficient to prevent the AMO-initiated inflammation of hypoxia. These results may explain the effectiveness of dexamethasone in the treatment of the systemic effects of alveolar hypoxia.

Study of dexamethasone, baicalin and octreotide on brain injury of rats with severe acute pancreatitis

OBJECTIVE

To investigate the protecting effects of dexamethasone (DXM), baicalin and octreotide on brain injury of rats with severe acute pancreatitis (SAP) and explore their underlying mechanism.

METHODS

This experiment was divided into two different parts: (1) In the first part, 90 SAP rats were randomly divided into a model control group and a DXM treated group (n = 45, respectively). (2) In the second part, 135 SAP rats were randomly divided into a model control group, a baicalin treated group and an octreotide treated group (n = 45, respectively). In two different experiments, the same number of normal rats were considered as the sham-operated group (n = 45, respectively). At 3, 6 and 12 h after operation, the pathological changes in the brain were observed. The expression levels of nuclear factor-κB (NF-κB), Bax and Bcl-2 proteins were detected and apoptosis indexes were calculated, using brain tissue microarray section.

RESULTS

(1) First part: The expression levels of Bax and Bcl-2 were significantly higher in the DXM treated group than those in the model control group at different time points, while the content of NF-κB protein and pathological changes were significantly lower in the treated group than those in the model control group (P < 0.05, P < 0.01 or P < 0.001). But the apoptotic indexes of brain tissue were not significantly different at different time points (P > 0.05). (2) Second part: At all time points after operation, the expression levels of NF-κB in the brain of treated groups were, to varying degrees, significantly lower than those in the model control group while the expression levels of Bcl-2 protein in baicalin and octreotide group were significantly higher than those in model control group (P < 0.01, P < 0.01 and P < 0.05, respectively). At 12 h after operation, the expression level of Bax protein in baicalin treated group was significantly higher than those in model control group and octreotide treated group (P < 0.05 and P < 0.01, respectively).

CONCLUSIONS

Dexamethasone, baicalin and octreotide can exert protective effects against brain injury in SAP rats mainly through inhibiting the expression of NF-κB protein.

Targeting P-selectin in acute pancreatitis

IMPORTANCE OF THE FIELD

Acute pancreatitis (AP) is a multifactorial disorder not fully understood yet. In particular, the pathogenetic pathways promoting a severe life-threatening course of AP are the subject of ongoing investigations. P-selectin has been shown to play a central role in the complex pathophysiology in AP as well as various other inflammatory conditions.

AREAS COVERED IN THIS REVIEW

P-selectin function in AP is reviewed with focus on its dual function as a mediator of leukocyte recruitment and cell adhesion, which implies the unique effect of linking both inflammation and coagulation, especially in the progression from mild to severe necrotizing AP. Potential therapeutic aspects are discussed with regard to the clinical situation.

WHAT THE READER WILL GAIN

A better understanding of the pathogenic role of P-selectin in AP and of the rationale for a therapeutic blockade.

TAKE HOME MESSAGE

P-selectin is a glycoprotein that mediates the adhesion of activated platelets and leukocytes to the vessel wall in various inflammatory conditions. Both pathophysiological steps are closely linked and play a key role in the course of severe AP. A treatment approach by inhibition of P-selectin could be of distinct interest as a therapeutic option in severe AP.