Anti-inflammatory effect of emodin on lipopolysaccharide-induced keratitis in Wistar rats

Emodin, a major bioactive extract of several Chinese herbs, has been shown to have a number of biological activities including antiviral, anti-inflammatory, anti-tumor, anti-fibrosis etc. In the present study, we investigated the effects of emodin as an anti-inflammatory agent on lipopolysaccharide (LPS) induced keratitis in Wistar rats. Clinical score, slit-lamp microscope were used to determine corneal inflammatory response. Corneal structure was observed by hematoxylin-eosin staining and transmission electron microscopy. Messenger ribonucleic acid levels of tight junction protein and cytokines were determined by reverse transcription- polymerase chain reaction. The activation of nuclear factor-kappa B (NF-κB) was detected with Western blot. We found that disorganized corneal tissue and cellular structures were observed in keratitis rats and emodin could deduce inflammatory response and improve corneal structure. Pretreated with emodin could up-regulate and down-regulate the mRNA expression of occludin and Interleukin-6. The activation of NF-κB could be inhibited partly after emodin treatment. In conclusion, emodin reduced corneal inflammation in LPS-induced keratitis in Wistar rats due to its capability of inhibition in NF-κB activation.