Diosmin alleviates retinal edema by protecting the blood-retinal barrier and reducing retinal vascular permeability during ischemia/reperfusion injury.

Abstract

BACKGROUND AND PURPOSE:

Retinal swelling, leading to irreversible visual impairment, is an important early complication in retinal ischemia/reperfusion (I/R) injury. Diosmin, a naturally occurring flavonoid glycoside, has been shown to have antioxidative and anti-inflammatory effects against I/R injury. The present study was performed to evaluate the retinal microvascular protective effect of diosmin in a model of I/R injury.

METHODS:

Unilateral retinal I/R was induced by increasing intraocular pressure to 110 mm Hg for 60 min followed by reperfusion. Diosmin (100 mg/kg) or vehicle solution was administered intragastrically 30 min before the onset of ischemia and then daily after I/R injury until the animals were sacrificed. Rats were evaluated for retinal functional injury by electroretinogram (ERG) just before sacrifice. Retinas were harvested for HE staining, immunohistochemistry assay, ELISA, and western blotting analysis. Evans blue (EB) extravasation was determined to assess blood-retinal barrier (BRB) disruption and the structure of tight junctions (TJ) was examined by transmission electron microscopy.

RESULTS:

Diosmin significantly ameliorated the reduction of b-wave, a-wave, and b/a ratio in ERG, alleviated retinal edema, protected the TJ structure, and reduced EB extravasation. All of these effects of diosmin were associated with increased zonular occluden-1 (ZO-1) and occludin protein expression and decreased VEGF/PEDF ratio.

CONCLUSIONS:

Maintenance of TJ integrity and reduced permeability of capillaries as well as improvements in retinal edema were observed with diosmin treatment, which may contribute to preservation of retinal function. This protective effect of diosmin may be at least partly attributed to its ability to regulate the VEGF/PEDF ratio.

• Authors: Nianting Tong, Zhenzhen Zhang, Wei Zhang, Yating Qiu, Yuanyuan Gong, Lili Yin, Qinghua Qiu, Xingwei Wu
• Journal: PloS one (PLoS One) Vol. 8 Issue 4 Pg. e61794 ( 2013) ISSN: 1932-6203 [Electronic] United States
• PMID: 23637907 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Eye Proteins
• Nerve Growth Factors
• Serpins
• Vascular Endothelial Growth Factor A
• pigment epithelium-derived factor
• Diosmin

Topics

• Animals
• Blood-Retinal Barrier (drug effects, metabolism, pathology)
• Capillary Permeability (drug effects)
• Diosmin (administration & dosage, pharmacology)
• Electroretinography
• Eye Proteins (metabolism)
• Male
• Nerve Growth Factors (metabolism)
• Papilledema (drug therapy, metabolism, pathology)
• Rats
• Reperfusion Injury (drug therapy, metabolism)
• Retina (drug effects, metabolism, pathology)
• Retinal Neurons (drug effects)
• Serpins (metabolism)
• Tight Junctions (drug effects, metabolism, ultrastructure)
• Vascular Endothelial Growth Factor A (metabolism)