Expression of High-Mobility Group Box 1 Protein (HMGB1) and Toll-Like Receptor 9 (TLR9) in Retinas of Diabetic Rats

BACKGROUND: Diabetic retinopathy (DR) and diabetic optic neuropathy are important complications of diabetes mellitus (DM) which can lead to blindness in diabetic patients. Recent studies showed that chronic low-grade inflammation is thought to be one of the important pathophysiological mechanisms in the occurrence and development of DR and diabetes optic neuropathy. This study explored the expressions of inflammatory factors HMGB-1 and TLR9. MATERIAL/METHODS: SD rats were randomly divided into a diabetic mellitus group and a control group. A DM rat model was produced by intraperitoneal injection of 1% STZ with 60 mg/Kg weight. At 4, 8, and 16 weeks after injection, the rats were sacrificed and eyeballs were enucleated for HE staining, immunohistochemistry, Western blot, and RT-PCR. RESULTS: We found that, compared with the control group, levels of HMGB1 and TLR9 in retinas were significantly increased in DM groups of different time courses. Furthermore, a significant correlation was found between HMGB1 and TLR9 (all P<0.05). CONCLUSIONS: Our results demonstrated that the HMGB1-TLR9 signaling pathway may be involved in the pathogenesis of diabetic retinopathy. Blockage of HMGB1 and/or TLR9 may represent a novel approach to treating diabetic retinopathy and diabetic optic neuropathy.