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Anti-inflammatory and ultrastructural effects of Turkish propolis in a rat model of endotoxin-induced uveitis
open access
Abstract
Introduction. Experimental animal models of acute uveitis, an inflammatory eye disease, can be established via endotoxin-induced inflammation. Propolis, a natural substance collected by honeybees from buds and tree exudates, has antioxidant, antibacterial, antiviral, and anti-inflammatory effects. We investigated the effects of propolis, obtained from the Sakarya province of Turkey, on endotoxin-induced uveitis using immunohistochemical, ultrastructural, and biochemical approaches.
Material and methods. Male Wistar albino rats (n = 6/group) received intraperitoneal (ip) lipopolysaccharide (LPS) endotoxin (150 μg/kg) followed by aqueous extract of propolis (50 mg/kg ip) or vehicle; two additional groups received either saline (control) or propolis only. After 24 h, aqueous humor (AH) was collected from both eyes of each animal for analysis of tumor necrosis factor-α (TNF-α) and hypoxia-inducible factor-1α (HIF-1α). Right eyeballs were paraffin-embedded for immunohistochemical staining of nuclear factor κB (NF-κB)/p65 and left eyeballs were araldite-embedded for ultrastructural analysis.
Results. Treatment of LPS-induced uveitis with propolis significantly reduced ciliary body NF-κB/p65 immunoreactivity and AH levels of HIF-1α and TNF-α. Ultrastructural analysis showed fewer vacuoles and reduced mitochondrial degeneration in the retinal pigment epithelium, as compared to the uveitis group. The intercellular spaces of the inner nuclear layer and outer limiting membrane were comparable with those of the control group; no polymorphonuclear cells or stasis was observed in intravascular or extravascular spaces.
Conclusions. This is the first report demonstrating an anti-inflammatory effect of Turkish propolis in a rat model of LPS-induced acute uveitis, suggesting a therapeutic potential of propolis for the treatment of inflammatory ophthalmic diseases.
Abstract
Introduction. Experimental animal models of acute uveitis, an inflammatory eye disease, can be established via endotoxin-induced inflammation. Propolis, a natural substance collected by honeybees from buds and tree exudates, has antioxidant, antibacterial, antiviral, and anti-inflammatory effects. We investigated the effects of propolis, obtained from the Sakarya province of Turkey, on endotoxin-induced uveitis using immunohistochemical, ultrastructural, and biochemical approaches.
Material and methods. Male Wistar albino rats (n = 6/group) received intraperitoneal (ip) lipopolysaccharide (LPS) endotoxin (150 μg/kg) followed by aqueous extract of propolis (50 mg/kg ip) or vehicle; two additional groups received either saline (control) or propolis only. After 24 h, aqueous humor (AH) was collected from both eyes of each animal for analysis of tumor necrosis factor-α (TNF-α) and hypoxia-inducible factor-1α (HIF-1α). Right eyeballs were paraffin-embedded for immunohistochemical staining of nuclear factor κB (NF-κB)/p65 and left eyeballs were araldite-embedded for ultrastructural analysis.
Results. Treatment of LPS-induced uveitis with propolis significantly reduced ciliary body NF-κB/p65 immunoreactivity and AH levels of HIF-1α and TNF-α. Ultrastructural analysis showed fewer vacuoles and reduced mitochondrial degeneration in the retinal pigment epithelium, as compared to the uveitis group. The intercellular spaces of the inner nuclear layer and outer limiting membrane were comparable with those of the control group; no polymorphonuclear cells or stasis was observed in intravascular or extravascular spaces.
Conclusions. This is the first report demonstrating an anti-inflammatory effect of Turkish propolis in a rat model of LPS-induced acute uveitis, suggesting a therapeutic potential of propolis for the treatment of inflammatory ophthalmic diseases.
Keywords
acute uveitis; propolis; lipopolysaccharide; HIF-1α; TNF-α; IHC; electron microscopy; rat
Title
Anti-inflammatory and ultrastructural effects of Turkish propolis in a rat model of endotoxin-induced uveitis
Journal
Folia Histochemica et Cytobiologica
Issue
Article type
Original paper
Pages
49-57
Published online
2016-05-10
Page views
2357
Article views/downloads
2523
DOI
10.5603/FHC.a2016.0004
Pubmed
Bibliographic record
Folia Histochem Cytobiol 2016;54(1):49-57.
Keywords
acute uveitis
propolis
lipopolysaccharide
HIF-1α
TNF-α
IHC
electron microscopy
rat
Authors
Salime Pelin Ertürküner
Elif Yaprak Saraç
Semil Selcen Göçmez
Hakan Ekmekçi
Zeynep Banu Öztürk
İsmail Seçkin
Özkan Sever
Kadircan Keskinbora