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

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 H 2 O 2 -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.

Effects of Daily Melatonin Supplementation on Visual Loss, Circadian Rhythms, and Hepatic Oxidative Damage in a Rodent Model of Retinitis Pigmentosa

“…A heating pad was used to maintain a stable temperature (37 °C) during the procedure. An Espion system from Diagnosys LLC (Cambridge, UK) presented the stimulus and acquired the data following a previously described protocol [ 24 ].…”

The mechanisms of natural products for eye disorders by targeting mitochondrial dysfunction

“…EGCG confers protection against ischemia injury ( Peng et al, 2008 ) and DR ( Silva et al, 2013 ). Its protective scope also extends to RP, where it not only lessens the visual function loss in P23H rats but also elevates the levels of antioxidant enzymes and reduces oxidative damage ( Perdices et al, 2022 ).…”

Oxidative Stress, Reductive Stress and Antioxidants in Vascular Pathogenesis and Aging

“…Epigallocatechin 3-gallate (EGCG), found in green tea as well as in cranberries, strawberries, blackberries, kiwis and other fruits, has insulin-mimetic actions on glucose metabolism and improves oxidative status. It has shown beneficial effects on vascular complications from diabetes, such as retinopathy, nephropathy and cardiovascular disease [94][95][96][97][98][99]. EGCG improves mitochondrial dysfunction, inhibits the formation of ROS and acts as a free radical scavenger [100][101][102].…”