Effect of Fenofibrate on the Expression of Inflammatory Mediators in a Diabetic Rat Model

Purpose: To investigate the mechanisms of anti-inflammatory and anti-oxidative effects of fenofibrate, a peroxisome proliferator-activated receptors-α agonist, in preventing diabetic retinopathy (DR) progression via a diabetic rat model. Methods: Diabetes was induced by intraperitoneal injection of streptozotocin in 6-week-old female Wistar rats. Diabetic rats were divided into diabetes without treatment (n = 10), diabetes treated with low dose fenofibrate (30 mg/kg/day) (n = 10) and high dose fenofibrate (100 mg/kg/day) (n = 10). Serum aqueous humor (AqH) and ocular tissues were gathered after 3-month treatment. Expressions of NF-κB and inflammatory chemokines (monocyte chemoattractant protein-1, fractalkine, and intercellular adhesion molecule-1) were detected by reverse transcription-polymerase chain reaction, Western blot, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), and electrophoretic mobility shift assay. The levels of oxidative biomarkers, including acrolein, nitrotyrosine, and 8-hydroxy-2'-deoxyguanosin (8-OHdG), were determined by IHC and ELISA. The reactive oxygen species (ROS) levels in serum and AqH were measured by chemiluminescence methods. Results: After 3 months of treatment, the expressions of mRNA and protein of monocyte chemoattractant protein-1, fractalkine, and intercellular adhesion molecule-1 in the retina of diabetic rats were significantly inhibited by fenofibrate in a dose-dependent manner. These effects were mediated by inhibition of NF-κB by fenofibrate. The levels of oxidative markers, including acrolein, nitrotyrosine, and 8-OHdG, decreased in the retina of diabetic rats after fenofibrate treatment. The ROS levels in the AqH of diabetic rats also suppressed by fenofibrate. Conclusions: Fenofibrate significantly inhibited the expressions of NF-κB and inflammatory chemokines and reduced oxidative products within diabetic retina. Treatment of fenofibrate might be beneficial to preventing DR progression.