Tyrosol ameliorates lipopolysaccharide-induced ocular inflammation in rats via inhibition of nuclear factor (NF)-κB activation

5-ALA/SFC Ameliorates Endotoxin-Induced Ocular Inflammation in Rats by Inhibiting the NF-κB Signaling Pathway and Activating the HO-1/Nrf2 Signaling Pathway

Sodium ferrous citrate (SFC) is involved in the metabolism of 5-aminolevulinic acid (5-ALA) and enhances its anti-inflammatory effects. The effects of 5-ALA/SFC on inflammation in rats with endotoxin-induced uveitis (EIU) have yet to be elucidated. In this study, during lipopolysaccharide injection, 5-ALA/SFC (10 mg/kg 5-ALA plus 15.7 mg/kg SFC) or 5-ALA (10 or 100 mg/kg) was administered via gastric gavage, wherein we saw that 5-ALA/SFC ameliorated ocular inflammation in EIU rats by suppressing clinical scores; by infiltrating cell counts, aqueous humor protein, and inflammatory cytokine levels; and by improving histopathological scores to the same extent as 100 mg/kg 5-ALA. Immunohistochemistry showed that 5-ALA/SFC suppressed iNOS and COX-2 expression, NF-κB activation, IκB-α degradation, and p-IKKα/β expression, and activated HO-1 and Nrf2 expression. Therefore, this study has investigated how 5-ALA/SFC reduces inflammation and revealed the pathways involved in EIU rats. 5-ALA/SFC is shown to inhibit ocular inflammation in EIU rats by inhibiting NF-κB and activating the HO-1/Nrf2 pathways.

Effects of Oral 5-Aminolevulinic Acid on Lipopolysaccharide-Induced Ocular Inflammation in Rats

This study aimed to investigate the anti-inflammatory effect of 5-aminolevulinic acid (5-ALA) on endotoxin-induced uveitis (EIU) in rats. EIU was induced in male Sprague Dawley rats by the subcutaneous injection of lipopolysaccharide (LPS). During LPS injection, 5-ALA diluted with saline was administered via gastric gavage. After 24 h, clinical scores were assessed after which aqueous humor (AqH) samples were obtained. The number of infiltrating cells, protein concentration, and levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), nitric oxide (NO), and prostaglandin E2 (PGE2) in AqH were measured. For histological examination, both eyes of some rats were enucleated. In vitro, a mouse macrophage cell line (RAW264.7 cells) was stimulated by LPS with or without 5-ALA. Western blot was used to analyze the expression of inducible NO synthase (iNOS) and cyclooxygenase-2. 5-ALA suppressed the EIU clinical scores, infiltrating cell number, and protein concentration while improving the histopathologic scores. In particular, 100 mg/kg 5-ALA reduced the concentrations of NO, PGE2, TNF-α, and IL-6 in AqH, similar to 1 mg/kg prednisolone. In addition, 5-ALA suppressed iNOS upregulation in LPS-stimulated RAW264.7 cells. Therefore, 5-ALA has an anti-inflammatory effect on EIU through the inhibition of the upregulation of inflammatory mediators.

Potential Effects of Phenolic Compounds That Can Be Found in Olive Oil on Wound Healing

The treatment of tissue damage produced by physical, chemical, or mechanical agents involves considerable direct and indirect costs to health care systems. Wound healing involves a series of molecular and cellular events aimed at repairing the defect in tissue integrity. These events can be favored by various natural agents, including the polyphenols in extra virgin olive oil (EVOO). The objective of this study was to review data on the potential effects of different phenolic compounds that can also be found in EVOO on wound healing and closure. Results of in vitro and animal studies demonstrate that polyphenols from different plant species, also present in EVOO, participate in different aspects of wound healing, accelerating this process through their anti-inflammatory, antioxidant, and antimicrobial properties and their stimulation of angiogenic activities required for granulation tissue formation and wound re-epithelialization. These results indicate the potential usefulness of EVOO phenolic compounds for wound treatment, either alone or in combination with other therapies. Human studies are warranted to verify this proposition.

A cell-permeable peptide inhibitor of p55PIK signaling alleviates ocular inflammation in mouse models of uveitis

PURPOSE

Previously we developed TAT-N24 as a synthetic cell-permeable peptide inhibitor of p55PIK signaling and demonstrated its anti-inflammatory effects. This study aimed to evaluate the potential of TAT-N24 as a new agent for the treatment of ocular inflammatory diseases.

METHODS

The endotoxin-induced uveitis (EIU) model was established by intravitreal injection of lipopolysaccharide (LPS) in BALB/c mice and experimental autoimmune uveitis (EAU) model was established by subcutaneous injection of a peptide spanning amino acid residues 161-180 of interphotoreceptor retinoid binding protein (IRBP161-180) with complete Freund's adjuvant (CFA) in B10.RIII mice. TAT-N24 was topically administered in EIU model and intraperitoneally administered in EAU model. The severity levels of uveitis were assessed by clinical and histopathological scores. The mRNA levels of inflammatory cytokines in iris-ciliary body (ICB) and retina were analyzed by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The protein levels of inflammatory factors were determined by ELISA or Western blotting.

RESULTS

The results showed that TAT-N24 alleviated clinical signs, decreased inflammatory cell infiltration and the expression of inflammatory cytokines in both EIU and EAU models. Furthermore, protein levels of tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in aqueous humor and mRNA and protein levels of NF-κB p65 in the ICB significantly decreased in EIU model. In EAU model, TAT-N24 application induced a significant decrease of IFN-gamma (IFN-γ) and interleukin-17 (IL-17) in the retina, which were secreted by Th1 and Th17 cells, respectively.

CONCLUSION

In conclusion, TAT-N24 suppressed intraocular inflammation in both EIU and EAU models, and the anti-inflammatory effects were mediated by suppressing the expression of inflammatory cytokines by PI3K/NF-κB signaling pathway. TAT-N24 could be potential candidate for the treatment of ocular inflammatory diseases.

Electrospun anti-inflammatory patch loaded with essential oils for wound healing

Wound healing is a complex process that consists of three overlapping phases: inflammation, proliferation, and remodeling. A bacterial infection can increase inflammation and delay this process. Microorganisms are closely related to the innate immune system, such as macrophages and neutrophils, as they can start an inflammatory cascade. Essential oils play an important role in the inhibition and prevention of bacterial growth due to their ability to reduce antimicrobial resistance. The possibility to find a strategy that combines antimicrobial and anti-inflammatory properties is particularly appealing for wound healing. In this work, we showcase a variety of patches based on electrospun polycaprolactone (PCL) nanofibers loaded with natural compounds derived from essential oils, such as thymol (THY) and tyrosol (TYR), to achieve reduced inflammation. In addition, we compared the effect these essential oils have on activated macrophages when incorporated into the PCL patch. Specifically, we demonstrate that PCL-THY resulted in more efficient down-regulation of pro-inflammatory genes related to the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κb) pathway when compared to PCL-TYR and the combination patch containing TYR and THY (i.e., PCL-TYR-THY). Furthermore, PCL-THY displayed low affinity for cell attachment, which may hinder wound adherence and integration. Overall, our results indicate that THY-loaded patches could serve as promising candidates for the fabrication of dressings that incorporate bactericidal and anti-inflammatory properties while simultaneously avoiding the limitations of traditional antibiotic-loaded devices.

Preventive effects of tyrosol, a natural phenolic compound, on anterior uveitis induced by anterior chamber paracentesis in healthy beagle dogs

We investigated the effects of tyrosol (Tyr) on anterior chamber paracentesis (ACP)–induced anterior uveitis in beagle dogs, as determined by protein and prostaglandin E2 (PGE2) concentrations in the aqueous humor (AH). Tyr at a dose of 100 or 200 mg/kg or 2.2 mg/kg of carprofen as a positive control was administered orally twice daily from 2.5 days before paracentesis. The initial ACP was performed in one eye of individual dogs and 0.5 ml AH was aspirated. The secondary AH was collected 60 min later. Pretreatment with 200 mg/kg of Tyr and carprofen significantly decreased aqueous protein and PGE2 concentrations compared to the control group. Overall, these findings suggested that Tyr was useful for the management of canine anterior uveitis.

PPARα Agonist Suppresses Inflammation after Corneal Alkali Burn by Suppressing Proinflammatory Cytokines, MCP-1, and Nuclear Translocation of NF-κB

We investigated the effect of a peroxisome proliferator-activated receptor α (PPARα) agonist after corneal alkali injury. Fenofibrate 0.05% (PPARα agonist group) or vehicle (Vehicle group) was topically instilled onto the rat cornea after injury. Histological, immunohistochemical, and real-time reverse transcription PCR analyses were performed. PPARα-positive cells were observed among basal cells of the corneal epithelium in normal and alkali-burned corneas. The number of infiltrating neutrophils and macrophages at the corneal limbus was lower in the PPARα agonist group. Interleukin-1β (IL-1β), IL-6, IL-8, monocyte chemoattractant protein-1 (MCP-1), and vascular endothelial growth factor-An mRNA expression was suppressed in the PPARα agonist group compared to the Vehicle group. mRNA levels of nuclear factor kappa B (NF-κB) in corneal tissue were not different. However, NF-κB was expressed in the cytoplasm of basal cells in the PPARα agonist group and in the nucleus in the Vehicle group. MCP-1 was more weakly expressed in the PPARα agonist group. The PPARα agonist inhibited inflammation during the early phase after injury. Anti-inflammatory effects of the PPARα agonist included prevention of up-regulation of proinflammatory cytokines and MCP-1, and prevention of inflammatory cell infiltration into the injured cornea. Thus, a PPARα agonist may be a promising treatment for corneal injury.

Anti-inflammatory Effects of Sinomenium Acutum Extract On Endotoxin-induced Uveitis in Lewis Rats

PURPOSE

Recent studies have reported the anti-inflammatory effect of Sinomenium acutum. We investigated the anti-inflammatory effect of sinomenine on endotoxin-induced uveitis in a rat model.

METHODS

Endotoxin-induced uveitis was induced in rat by lipopolysaccharide (LPS) immunization. Sinomenine (50mg/kg and 100mg/kg) was administered at 30 minutes before, 6 hours and 12 hours after LPS immunization. Clinical and histological severity was evaluated. Protein concentration and levels of tumor necrosis factor (TNF)-α and prostaglandin (PG)-E2 in aqueous humor were measured. Expression of activated Nuclear factor (NF)-κB p65 in ciliary body was also observed.

RESULTS

Clinical and histological severities were significantly milder in sinomenine-treated rat than in controls (P < 0.001). Sinomenine suppressed protein leakage and down-regulated the production of TNF-α and PG-E2 in a dose-dependent manner. Sinomenine treatment suppressed the translocation of the NF-κB p65 subunit into the nuclei.

CONCLUSION

Systemic administration of sinomenine suppressed the inflammation of ocular tissues. These findings suggest that sinomenine could be a novel therapeutic agent for the control of endogenous ocular inflammatory disease.

Relative potency of tyrosol in the treatment of endotoxin-induced uveitis in rats

Tyrosol (Tyr) is a natural phenolic antioxidant with diverse biological activities. We compared the anti-inflammatory effects of intravenously administered Tyr versus prednisolone (PSL) in an endotoxin-induced uveitis (EIU) rat model. Intravenous administration of 100 mg/kg Tyr was performed 2 hr before, simultaneously and 2 hr after lipopolysaccharide (LPS) injection. Tyr treatment was associated with decreased inflammatory cell number, protein concentration, tumor necrosis factor (TNF)-α, PGE2 and NO levels in AqH and improvements in histopathologic evidence of EIU in ocular tissue at 24 hr after LPS injection. 100 mg/kg Tyr and 1 mg/kg PSL (administered on the same schedule as Tyr) had comparable anti-inflammatory effects. Taken together, Tyr may represent a promising therapeutic agent for the management of intraocular inflammatory diseases.