Systemic epigallocatechin gallate protects against retinal degeneration and hepatic oxidative stress in the P23H-1 rat

Lorena Perdices; Lorena Fuentes-Broto; Francisco Segura; Ana Cavero; Elvira Orduna-Hospital; Gema Insa-Sánchez; Ana Isabel Sánchez-Cano; Laura Fernández-Sánchez; Nicolás Cuenca; Isabel Pinilla

doi:10.4103/1673-5374.320990

Systemic epigallocatechin gallate protects against retinal degeneration and hepatic oxidative stress in the P23H-1 rat

Neural Regen Res. 2022 Mar;17(3):625-631. doi: 10.4103/1673-5374.320990.

Affiliations

¹ Aragón Institute for Health Research (IIS Aragón), Zaragoza, Spain.
² Pharmacology, Physiology & Legal and Forensic Medicine, University of Zaragoza, Zaragoza, Spain.
³ Department of Applied Physics, University of Zaragoza, Zaragoza, Spain.
⁴ Health Sciences Faculty, San Jorge University, Villanueva de Gállego, Spain.
⁵ Department of Ophthalmology, Miguel Servet University Hospital, Zaragoza, Spain.
⁶ Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain.
⁷ Department of Surgery, Gynecology and Obstetrics, University of Zaragoza; Department of Ophthalmology, Lozano Blesa University Hospital, Zaragoza, Spain.

Abstract

Retinitis pigmentosa (RP) is a group of inherited retinal disorders that lead to photoreceptor loss. RP has been reported to be related to oxidative stress, autophagy, and inflammation. (-)-Epigallocatechin gallate (EGCG), the most abundant catechin-based flavonoid in green tea leaves, has significant antioxidant, anti-carcinogenic, antimicrobial, and neuroprotective properties. EGCG, given its low molecular weight and hydrophilic properties, can cross the blood-retinal barrier and is able to reach different ocular tissues such as the lens, cornea, and retina. EGCG has been shown to provide retinal protection against ischemia; sodium nitroprusside-, N-methyl-D-aspartate-, lipopolysaccharide-, light-, sodium iodate-, or H₂O₂-induced damage and diabetic retinopathy. This suggests that systemic EGCG administration has the potential to protect against retinal degenerative or neurodegenerative diseases such as RP. The aim of this work was to investigate whether EGCG can protect against RP progression in the animal P23H line 1, the model of RP. Albino P23H rats were crossed with pigmented Long Evans rats to produce offspring exhibiting the clinical features of RP. Pigmented P23H rats were treated via intraperitoneal injection with saline or EGCG at a dose of 25 mg/kg every week from P100 to P160 and then compared to wild-type Long Evans rats. Rats treated with EGCG showed better visual and retinal electrical function with increased contrast sensitivity and b-wave values compared with those observed in P23H rats treated with vehicle. EGCG reduced lipid peroxidation and increased total antioxidant capacity and catalase and superoxide dismutase activities. No differences were observed in visual acuity, nitrate levels, nitrite levels or glutathione S-transferase activity. In conclusion, EGCG not only reduced the loss of visual function in P23H rats but also improved the levels of antioxidant enzymes and reduced oxidative damage. This study was approved by the Institutional Animal Care and Use Committee (CEICA) from the University of Zaragoza under project license PI12/14 on July 11, 2014.

Keywords: antioxidants; contrast sensitivity; electroretinogram; green tea; neurodegeneration; oxidative stress; retinal degeneration; retinitis pigmentosa; systemic; visual acuity.