Effects of Carvacrol on Survival, Mesenteric Blood Flow, Aortic Function and Multiple Organ Injury in a Murine Model of Polymicrobial Sepsis

Carvacrol protects rats against bleomycin-induced lung oxidative stress, inflammation, and fibrosis

The main objective of this study was to investigate the potential efficacy of carvacrol (CAR) in mitigating bleomycin (BLM)-induced pulmonary fibrosis (PF). Sixty-six male Wistar rats were assigned into two main groups of 7 and 21 days. They were divided into the subgroups of control, BLM, CAR 80 (only for the 21-day group), and CAR treatment groups. The CAR treatment groups received CAR (20, 40, and 80 mg/kg, orally) for 7 or 21 days after an instillation of BLM (5 mg/kg, intratracheally). Results indicated that BLM significantly increased total cell count in bronchoalveolar lavage fluid and the percentages of neutrophils and lymphocytes, and reduced the percentage of macrophages. CAR dose-dependently decreased total cell count and the percentage of neutrophils and lymphocytes. CAR significantly reduced thiobarbituric acid reactive substances and hydroxyproline levels and elevated the total thiol level and catalase, superoxide dismutase, and glutathione peroxidase activities in BLM-exposed rats. Furthermore, CAR decreased the transforming growth factor-β1, connective transforming growth factor, and tumor necrosis factor-α on days 7 and 21. BLM increased interferon-γ on day 7 but decreased its level on day 21. However, CAR reversed interferon-γ levels on days 7 and 21. Based on histopathological findings, BLM induced inflammation on days 7 and 21, but for induction of fibrosis, 21-day study showed more fibrotic injuries than the 7-day group. CAR showed the improvement of fibrotic injuries. The effect of CAR against BLM-induced pulmonary fibrosis is possibly due to its antioxidant, anti-inflammatory, and antifibrotic activity.

Carvacrol protects mice against LPS-induced sepsis and attenuates inflammatory response in macrophages by modulating the ERK1/2 pathway

Macrophages play an important role in the development of life-threatening sepsis, which is characterized by multiorgan dysfunction, through their ability to produce inflammatory cytokines. Carvacrol is a phenolic compound that has been confirmed to possess strong anti‑inflammatory activity. In this study, we mainly investigated the effect of carvacrol on lipopolysaccharide (LPS)-induced macrophage proinflammatory responses and endotoxic shock. The results showed that carvacrol significantly reduced mouse body weight loss and ameliorated pathological damage to the liver, lung, and heart under LPS-induced sepsis. Carvacrol attenuated inflammatory responses by inhibiting the LPS-induced production of inflammatory cytokine interleukin-6 (IL-6) in vivo and in vitro. Mechanistically, carvacrol inhibited IL-6 production mainly through the ERK1/2 signalling pathway in macrophages. Furthermore, carvacrol improved the survival of septic mice. This study sheds light on the role of carvacrol in the pathogenesis of LPS-induced sepsis, and thus, its potential in treating sepsis patients may be considered.

Arum orientale

Background: Sepsis is a lethal clinical syndrome that results from dysregulated systemic inflammatory response of the body due to the invasion of pathogens, especially bacteria. Despite advances in medical care and therapy, sepsis is still one of the major causes of death in intensive care units and no decisive medical treatment is available against that. Studies have suggested that some Arum species have anti-bacterial properties. The present study investigated the effects of hydroalcoholic extract of Arum orientale, on cecal ligation and puncture (CLP) induced sepsis in rats. Methods: CLP method was used for induction of sepsis in rats. Hydroalcoholic extract of A. orientale was injected intraperitoneally with doses of 80 and 640 mg/Kg body weight at times of 0, 1, 3, 6 and 24 h after the surgery. Antibacterial activity, hemodynamic parameters, myeloperoxidase (MPO) activity and survival rate were measured after 72 h. Results: Hydroalcoholic extract of A. orientale showed antibacterial activities as potent as gentamycin against Escherichia coli. Administration of the extract with a dose of 80 mg/Kg body weight increased significantly hemodynamic parameters such as mean arterial pressure (p<0.05)and decreased optical density (OD) (p<0.05) of blood. The extract also increased serum MPO activity (p<0.01) and reduced survival rate to 20%. Conclusion: This study for the first time showed that hydroalcoholic extract of A. oriental acts as a double edge sword in the treatment of CLP-induced sepsis. This extract showed antibacterial properties and also improved hemodynamic parameters but decreased survival rate, that might be through pro-inflammatory effects.

Anti-inflammatory and antioxidant activity of carvacrol in the respiratory system: A systematic review and meta-analysis

Carvacrol is a monoterpene present in the essential oil of a number of plants and has been widely used in traditional medicine because it is considered to have a range of therapeutic effects including in relation to respiratory disease. To conduct a systematic review and meta-analysis to assess the anti-inflammatory and antioxidant activities of carvacrol when used in the treatment of respiratory disorders. A comprehensive literature search using Scopus, MEDLINE-PubMed, Cochrane and Web of Science was undertaken. Papers related to the anti-inflammatory or antioxidant properties of carvacrol in the treatment of an injury in the respiratory system in in vivo studies and published in the period up to and including August 2019. A total of 152 studies were initially identified, with only 17 meeting the inclusion criteria. Five of the studies were performed in humans, and 12 were performed in rodents. Among the 17 studies included in the systematic review, we performed the meta-analysis with nine of the studies with animals. Carvacrol had a positive effect on the reduction of interleukin (IL)-1β, IL-4, IL-8 and malondialdehyde (MDA); however, the analysis indicated that carvacrol had no effect on IL-6 and tumor necrosis factor alpha (TNF-α), probably due to the methodological quality of the studies and their heterogeneity. Current evidence supports the antioxidant and anti-inflammatory effects of carvacrol, but its relationship with the reduction of some inflammatory mediators in animals with lung injury needs further elucidation.

Acute Increase in O-GlcNAc Improves Survival in Mice With LPS-Induced Systemic Inflammatory Response Syndrome

Sepsis is a systemic inflammatory response syndrome (SIRS) resulting from a severe infection that is characterized by immune dysregulation, cardiovascular derangements, and end-organ dysfunction. The modification of proteins by O-linked N-acetylglucosamine (O-GlcNAcylation) influences many of the key processes that are altered during sepsis, including the production of inflammatory mediators and vascular contractility. Here, we investigated whether O-GlcNAc affects the inflammatory response and cardiovascular dysfunction associated with sepsis. Mice received an intraperitoneal injection of lipopolysaccharide (LPS, 20 mg/Kg) to induce endotoxic shock and systemic inflammation, resembling sepsis-induced SIRS. The effects of an acute increase in O-GlcNAcylation, by treatment of mice with glucosamine (GlcN, 300 mg/Kg, i.v.) or thiamet-G (ThG, 150 μg/Kg, i.v.), on LPS-associated mortality, production and release of cytokines by macrophages and vascular cells, vascular responsiveness to constrictors and blood pressure were then determined. Mice under LPS-induced SIRS exhibited a systemic and local inflammatory response with increased levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor (TNF-α), as well as severe hypotension and vascular hyporesponsiveness, characterized by reduced vasoconstriction to phenylephrine. In addition, LPS increased neutrophil infiltration in lungs and produced significant lethality. Treatment with GlcN and ThG reduced systemic inflammation and attenuated hypotension and the vascular refractoriness to phenylephrine, improving survival. GlcN and ThG also decreased LPS-induced production of inflammatory cytokines by bone marrow-derived macrophages and nuclear transcription factor-kappa B (NF-κB) activation in RAW 264.7 NF-κB promoter macrophages. Treatment of mice with ThG increased O-glycosylation of NF-κB p65 subunit in mesenteric arteries, which was associated with reduced Ser⁵³⁶ phosphorylation of NF-κB p65. Finally, GlcN also increased survival rates in mice submitted to cecal ligation and puncture (CLP), a sepsis model. In conclusion, increased O-GlcNAc reduces systemic inflammation and cardiovascular disfunction in experimental sepsis models, pointing this pathway as a potential target for therapeutic intervention.

The inclusion complex of carvacrol and β-cyclodextrin reduces acute skeletal muscle inflammation and nociception in rats

BACKGROUND

Skeletal muscle inflammation is strongly associated with pain and may impair regeneration and functional recovery after injury. Since anti-inflammatory and antinociceptive effects have been described for the inclusion complex of carvacrol and β-cyclodextrin (βCD-carvacrol), this study investigated the effects of βCD-carvacrol in a model of acute skeletal muscle inflammation.

METHODS

Muscle injury was induced in male Wistar rats by injection of 3% carrageenan in the gastrocnemius muscle. Rats were orally pretreated with saline (vehicle) or βCD-carvacrol (20, 40, 80 and 180 mg/kg) one hour before administration of carrageenan.

RESULTS

The injection of carrageenan in the gastrocnemius muscle increased tissue myeloperoxidase (MPO) activity (p < 0.001), edema (p < 0.001) and the levels of tumoral necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, macrophage inflammatory protein (MIP-2), but not IL-10 levels. Also, it increased mechanical hyperalgesia and decreased the grip force of animals. Pretreatment with βCD-carvacrol (80 or 160 mg/kg) significantly decreased muscle MPO activity and edema 24 h after injury in comparison to vehicle-pretreated group. Animals pretreated with βCD-carvacrol (160 mg/kg) presented significantly lower levels of IL-1β, IL-6 and MIP-2 and higher levels of IL-10 six hours after induction and lower levels of TNF-α and MIP-2 after 24 h when compared to the vehicle group. Pretreatment with βCD-carvacrol also reduced mechanical hyperalgesia and limited the decrease of grip force (80 or 160 mg/kg; p < 0.001) 6 and 24 h after injury.

CONCLUSION

These results show that βCD-carvacrol reduces inflammation and nociception in a model of acute injury to skeletal muscles.

Heme Oxygenase-1 Reduces Sepsis-Induced Endoplasmic Reticulum Stress and Acute Lung Injury

Background

Sepsis leads to severe acute lung injury/acute respiratory distress syndrome (ALI/ARDS) that is associated with enhanced endoplasmic reticulum (ER) stress. Heme oxygenase-1 (HO-1), an ER-anchored protein, exerts antioxidant and protective functions under ALI. However, the role of HO-1 activation in the development of endoplasmic reticulum (ER) stress during sepsis remains unknown.

Methods

Cecal ligation and puncture (CLP) model was created to induce septic ALI. Lung tissue ER stress was measured 18 hours after CLP. The effects of HO-1 on ER stress during septic ALI were investigated in vivo using HO-1 agonist hemin and antagonist ZnPP.

Results

Compared with the sham group, ER stress in septic lung increased significantly 18 hours after CLP, which was significantly reduced by pretreatment with the ER inhibitor 4-phenylbutyrate (4-PBA). The lung injury score and the lung wet to dry (W/D) ratio in lungs were significantly reduced in septic rats after ER stress inhibition. Similarly, lung ER stress-related genes' (PERK, eIF2-α, ATF4, and CHOP) levels were attenuated after ER stress inhibition. Furthermore, HO-1 activation by hemin reduced p-PERK, p-eIF2-α, ATF4, and CHOP protein expression and oxidative stress and lung cell apoptosis. Additionally, HO-1 antagonist could aggregate the ER stress-related ALI.

Conclusions

ER stress was activated during CLP-induced ALI, which may represent a mechanism by which CLP induces ALI. HO-1 activation could inhibit CLP-induced lung ER stress and attenuate CLP-induced ALI.