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.