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Grape seed proanthocyanidin extract protects the retina against early diabetic injury by activating the Nrf2 pathway
Yan Sun1, Caimei Xiu2, Wei Liu1
1Department of Ophthalmology, Jinan Second People's Hospital, Jinan, Shandong 250001, P.R. China.
Abstract:
The present study aimed to investigate whether grape seed proanthocyanidin extract (GSPE) has a protective effect on diabetic retinal function. A total of 30 Wistar rats were randomly divided into three equal groups, including the control, diabetic and GSPE-treated diabetic groups. Retinal tissue was harvested and subsequently stained with hematoxylin and eosin. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and methane dicarboxylic aldehyde (MDA) levels were evaluated using respective assay kits; whereas nuclear erythroid 2-related factor 2 (Nrf2) and heme oxygenase (HO)-1 expression levels were assessed by immunohistochemical and western blot analysis. Cell apoptosis in the retina was determined using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method. The results showed that the structure of the retina was damaged in diabetic rats, as compared with the control rats. Notably, the structure of the retina improved in the GSPE-treated diabetic group, as compared with the diabetic group. SOD and GSH-Px activities were significantly increased in the retina of rats in the GSPE-treated diabetic group, as compared with the diabetic group (P=0.011 and P=0.001, respectively). Furthermore, a significant reduction in MDA was detected (P=0.013) and the expression levels of Nrf2 and HO-1 in the bladders of rats in the GSPE-treated diabetic group were significantly increased, as compared with the diabetic group (P=0.038 and P=0.043, respectively). Apoptosis of retinal cells was significantly increased in the diabetic group, as compared with the control group (P<0.001); a significant reduction was also detected in the GSPE-treated diabetic group, as compared with the diabetic group (P=0.014). These results demonstrate that GSPE administration may protect the retina against hyperglycemic damage, possibly by ameliorating oxidative stress-mediated injury via the activation of the Nrf2 pathway.
Insights
Grape seed proanthocyanidin extract (GSPE) protects diabetic retinal function by reducing oxidative stress. GSPE treatment improved retinal structure and reduced cell apoptosis in diabetic rats.
Area of Science:
- Ophthalmology
- Diabetology
- Pharmacology
Background:
- Diabetic retinopathy is a leading cause of vision loss.
- Oxidative stress plays a critical role in the pathogenesis of diabetic retinopathy.
- Grape seed proanthocyanidin extract (GSPE) possesses antioxidant properties.
Purpose of the Study:
- To investigate the protective effects of GSPE on diabetic retinal function.
- To explore the underlying mechanisms of GSPE's action in diabetic retinas.
Main Methods:
- Wistar rats were divided into control, diabetic, and GSPE-treated diabetic groups.
- Retinal tissue was analyzed for structural changes, oxidative stress markers (SOD, GSH-Px, MDA), and apoptosis.
- Expression of Nrf2 and HO-1 was assessed via immunohistochemistry and Western blot.
Main Results:
- Diabetic rats exhibited retinal structural damage and increased cell apoptosis.
- GSPE treatment improved retinal structure and significantly reduced apoptosis in diabetic rats.
- GSPE administration increased SOD and GSH-Px activities, decreased MDA levels, and upregulated Nrf2 and HO-1 expression.
Conclusions:
- GSPE demonstrates a protective effect against hyperglycemic damage to the retina.
- GSPE ameliorates oxidative stress-mediated injury through the activation of the Nrf2 pathway.
- GSPE holds potential as a therapeutic agent for diabetic retinopathy.
