Green Tea Is Neuroprotective in Diabetic Retinopathy

Author(s)

Silva, Kamila C. ^[1] ; Rosales, Mariana A. B. ^[1] ; Hamassaki, Dania E. ^[2] ; Saito, Kelly C. ^[2] ; Faria, Aline M. ^[1] ; Ribeiro, Patricia A. O. ^[1] ; Lopes de Faria, Jose B. ^[1] ; Lopes de Faria, Jacqueline M. ^[1]

Affiliation

^[1] State Univ Campinas Unicamp, Renal Pathophysiol Lab, Fac Med Sci, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Dept Histol & Embryol, Inst Biomed Sci, Sao Paulo - Brazil

• Document type: Journal article
• Source: INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE; v. 54, n. 2, p. 1325-1336, FEB 2013.
• Web of Science Citations: 49

Abstract

PURPOSE. Green tea (GT), widely studied for its beneficial properties in protecting against brain ischemia, is a rich source of polyphenols, particularly (-)-epigallocatechin gallate (EGCG). The results presented here demonstrate the beneficial effects of GT in diabetic retinas and in retinal cells under diabetic conditions. METHODS. Diabetes was induced in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats. Treatment animals received GT orally for 12 weeks. A vehicle was administered orally to the control animals. The protective effects of GT were also evaluated in Muller and in ARPE-19 cells. RESULTS. In diabetic rats, there was an increase in the expression of glial fibrillary acidic protein (GFAP), oxidative retinal markers, and glutamine synthetase levels. In addition, there was a decrease in occludin and glutamate transporter and receptor. Diabetic SHR also demonstrated blood-retinal barrier breakdown and impaired electroretinography results. Muller cells exposed to high-glucose medium produced higher levels of reactive oxygen species (ROS) and glutamine synthetase but reduced levels of glutathione, glutamate transporter, and glutamate receptor. Similarly, ARPE-19 cells exhibited increased ROS production accompanied by decreased expression of claudin-1 and glutamate transporter. Treatment with GT fully restored all the above-mentioned alterations in diabetic animals as well as in retinal cells. CONCLUSIONS. GT protected the retina against glutamate toxicity via an antioxidant mechanism. These findings reveal a novel mechanism by which GT protects the retina against neurodegeneration in disorders such as diabetic retinopathy. (Invest Ophthalmol Vis Sci. 2013;54:1325-1336) DOI:10.1167/iovs.12-10647 (AU)

• FAPESP's process: 08/57560-0 - Effects of green tea (Camellia sinensis), cocoa and nitric oxide donor on diabetic nephropathy and retinopathy: contribution of the reduction of oxidative stress and inflammation and elevation of nitric oxide
• Grantee: Jose Butori Lopes de Faria
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 10/11514-7 - Does green tea (Camellia sinensis, CS) present neuroprotector effect in the pathogenesis of diabetic retinopathy? In vitro studies in primary rat Muller cell culture to investigate the possible molecular mechanisms involved in neuroprotective effects of CS
• Grantee: Jacqueline Mendonça Lopes de Faria
• Support Opportunities: Regular Research Grants