Purchase this article with an account.
Mariana A. Rosales, Kamila C. Silva, Jose B. Lopes de Faria, Jacqueline M. Lopes de Faria; Polyphenol Enriched Cocoa Protects the Retinal Function in Experimental Model of Diabetes. An In Vivo and In Vitro Study. Invest. Ophthalmol. Vis. Sci. 2012;53(14):5411.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
It has been demonstrated that polyphenol compounds display antioxidant and anti-inflammatory properties and are attributed to protect against diabetic complications. Diabetic retinopathy (DR) is associated with early alterations of the blood retinal barrier (BRB) breakdown in its pathogenesis. The objective of this study was to investigate the effects of polyphenol enriched cocoa in neural retina and in outer BRB function in experimental diabetic (DM) models.
Diabetes was induced by streptozotocin in WKY rats with 10 weeks of age. The rats were randomized into 4 groups, treated or not with polyphenol enriched cocoa or cocoa without polyphenols (placebo): placebo treated control (PL-CT), placebo treated diabetic (PL-DM), cocoa treated control (CC-CT) and cocoa treated diabetic (CC-DM) in a dose of 190 mg/kg of cocoa/placebo by oral gavage daily for 16 weeks. To access the possible mechanisms involved, in vitro studies with human retinalpigment epithelium cells line (ARPE-19) exposed to high glucose (HG-30 mM) or HG + CC (10 ng, 100 ng and 1 µg/ml) for 24 hours were conducted.
The retinal function, evaluated by electroretinogram (ERG), showed a decrease in b-wave amplitude (pos-photoreceptor response) in PL-DM group compared with PL-CT accompanied by increase of GFAP and inducible nitric oxide synthase (iNOS) expressions. The treatment with polyphenol enriched cocoa prevented the above abnormalities. The ARPE-19 cells in HG medium, revealed a significant increasing in total intracellular reactive oxygen species (ROS) production and the presence of the cocoa inhibited about 30% of this ROS increase. The integrity of BRB, evaluated by expression of claudin-1, a tight junction protein, was decreased in cells exposed to HG with decreased permeability to FICT-dextran and the cocoa treatment prevented these abnormalities.
In diabetic rats, there was an increased GFAP and iNOS expressions accompanied by a significant impairment in ERG. In ARPE-19 exposed to mimetic diabetic milieu conditions, there was increase in ROS production, decreased expression of claudin-1 with decreased paracellular permeability. The polyphenol enriched cocoa, either in in vivo as in vitro study demonstrated a protective effect possible by maintaining the oxidative status.
This PDF is available to Subscribers Only