Kathleen J McClinton1, Michel Aliani1,2, Sharee Kuny3, Yves Sauvé3,4, Miyoung Suh1,2,5. 1. a Department of Food and Human Nutritional Sciences , University of Manitoba , Winnipeg , Canada. 2. b Division of Neurodegenerative Disorders , St. Boniface Albrechtsen Research Centre , Winnipeg , Canada. 3. d Department of Physiology , University of Alberta , Edmonton , Canada. 4. e Department of Ophthalmology and Visual Sciences , University of Alberta , Edmonton , Canada. 5. c Canadian Centre for Agri-Food Research in Health and Medicine , St. Boniface Albrechtsen Research Centre , Winnipeg , Canada.
Abstract
OBJECTIVE: This study was designed to examine the supplementation of a carotenoid-rich carrot powder, on retina function and carotenoid metabolism in non-diabetic control and type 1 diabetic animals. METHODS: Male Wistar rats (n = 30) were randomly assigned to diets supplemented with (n = 15) or without (n = 15) carrot powder enriched diets (150 g/kg diet). After 3 weeks of diet adaptation, 8 rats in each group were treated with streptozotocin (iv) to induce type 1 diabetes and fed for a further 9 wk. Retinal function was assessed with the electroretinogram (ERG). Hepatic and plasma retinoids and carotenoids were measured by ultra-performance liquid chromatography. RESULTS: Non-diabetic control rats fed the carrot diet had significantly (p < 0.02) higher rod- and cone- driven post-synaptic b-wave amplitudes, respectively, compared to those fed the control diet. These functional changes correlated with higher (p < 0.05) liver levels of carotenoids (α- and β- carotene) and retinoids. In diabetic rats, carrot diet exacerbated retina dysfunction; the amplitudes for most of rod- and cone-driven ERG components were the lowest amplitudes among all groups (p < 0.02). Diabetic rats fed the carrot diet had lower hepatic retinol and retinyl palmitate, while having higher α- and β-carotene levels, indicating diminished hepatic conversion of carotenoids into retinoids. DISCUSSION: Dietary supplementation of high dose dietary carotenoids plays a beneficial role on healthy rat retina function, but exerts a detrimental effect in diabetes, which warrants undertaking detailed mechanistic studies.
OBJECTIVE: This study was designed to examine the supplementation of a carotenoid-rich carrot powder, on retina function and carotenoid metabolism in non-diabetic control and type 1 diabetic animals. METHODS: Male Wistar rats (n = 30) were randomly assigned to diets supplemented with (n = 15) or without (n = 15) carrot powder enriched diets (150 g/kg diet). After 3 weeks of diet adaptation, 8 rats in each group were treated with streptozotocin (iv) to induce type 1 diabetes and fed for a further 9 wk. Retinal function was assessed with the electroretinogram (ERG). Hepatic and plasma retinoids and carotenoids were measured by ultra-performance liquid chromatography. RESULTS:Non-diabetic control rats fed the carrot diet had significantly (p < 0.02) higher rod- and cone- driven post-synaptic b-wave amplitudes, respectively, compared to those fed the control diet. These functional changes correlated with higher (p < 0.05) liver levels of carotenoids (α- and β- carotene) and retinoids. In diabeticrats, carrot diet exacerbated retina dysfunction; the amplitudes for most of rod- and cone-driven ERG components were the lowest amplitudes among all groups (p < 0.02). Diabeticrats fed the carrot diet had lower hepatic retinol and retinyl palmitate, while having higher α- and β-carotene levels, indicating diminished hepatic conversion of carotenoids into retinoids. DISCUSSION: Dietary supplementation of high dose dietary carotenoids plays a beneficial role on healthy rat retina function, but exerts a detrimental effect in diabetes, which warrants undertaking detailed mechanistic studies.
Authors: Brenda Fernanda Moreira Castro; Carolina Nunes da Silva; Lídia Pereira Barbosa Cordeiro; Sarah Pereira de Freitas Cenachi; Daniel Vitor Vasconcelos-Santos; Renes Resende Machado; Luiz Guilherme Dias Heneine; Luciana Maria Silva; Armando Silva-Cunha; Silvia Ligório Fialho Journal: Curr Res Pharmacol Drug Discov Date: 2022-05-11