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

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-a (TNF-a) and hypoxia-inducible factor-1a (HIF-1a). Right eyeballs were paraffin-embedded for immunohistochemical staining of nuclear factor kB (NF-kB)/p65 and left eyeballs were araldite-embedded for ultrastructural analysis. Results. Treatment of LPS-induced uveitis with propolis significantly reduced ciliary body NF-kB/p65 immunoreactivity and AH levels of HIF-1a and TNF-a. 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.

Insight on Propolis from Mediterranean Countries: Chemical Composition, Biological Activities and Application Fields

“…Contradictory, Eraslan et al [254] declared that the evaluation of Turkish propolis from Erzurum led to the conclusion that the tested sample was not able to completely eliminate the free radicals and the other adverse effects generated in rats treated with sodium fluoride. In the same field, Ertürküner et al [255] explored the effects of Turkish propolis on endotoxininduced uveitis on male Wistar albino rats and have revealed that propolis can act as anti-inflammatory agent and could be used for the treatment of ophthalmic diseases. Besides, propolis from Turkey showed immunomodulatory, antioxidant and antiinflammatory activities in animal models.…”

Evaluation of prophylactic and therapeutic effects of sildenafil on acute radiation proctitis in rats

“…Under observation of a pathologist, the tissues were cut into 3 equal horizontal pieces and put into relevant fixatives 17 .…”

“…5µm-thick sections were stained immunohistochemically by using Streptavidin-Biotin-Peroxidase method with monoclonal and polyclonal antibodies tagged to indicate cell and tissue antigens, according to previously described method 17 .…”

“…Positively stained cells with relevant antigens were analyzed semi-quantitatively in terms of staining intensity (modified H-SCORE analysis) 17 . Thereby rectal localization of these proteins and variance of the staining intensity and regional differences were determined.…”

Different propolis samples, phenolic content, and breast cancer cell lines: Variable cytotoxicity ranging from ineffective to potent

“…It has been shown that propolis possesses a wide spectrum of biological properties such as anticancer, antioxidant, anti‐inflammatory, antibiotic, and antifungal activities . Recently, propolis is being widely used in foods and beverages by virtue of preventing or ameliorating various illnesses including heart disease , diabetes , inflammatory diseases and cancer . Propolis is a natural and adhesive substance produced by honeybees, Apis melifera , by collecting various constituents from tree exudates, leaf buds, and other parts of plants .…”