Anti-inflammatory and ultrastructural effects of Turkish propolis in a rat model of endotoxin-induced uveitis.
BACKGROUND
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.


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.
Salime Pelin
SP
Ertürküner
Elif
E
Yaprak Saraç
Semil Selcen
SS
Göçmez
Hakan
H
Ekmekçi
Zeynep Banu
ZB
Öztürk
İsmail
İ
Seçkin
Özkan
Ö
Sever
Bahcesehir University, Faculty of Medicine, Ophthalmology Department, Sahrayı Cedid District, Yenisahra, Kadıkoy/Istanbul. prpendx@gmail.com.
Kadircan
K
Keskinbora
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001082:Aqueous Humor / Q000378:metabolism; D002924:Ciliary Body / Q000187:drug effects / Q000378:metabolism; D004195:Disease Models, Animal; D007150:Immunohistochemistry; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D011429:Propolis / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D051996:Transcription Factor RelA / Q000378:metabolism; D014605:Uveitis / Q000139:chemically induced / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology
D000893:Anti-Inflammatory Agents; D008070:Lipopolysaccharides; D051996:Transcription Factor RelA; D011429:Propolis
HIF-1α; IHC; TNF-α; acute uveitis; electron microscopy; lipopolysaccharide; propolis; rat