Carnosine supplementation and retinal oxidative parameters in a high-calorie diet rat model.

BACKGROUND: To assess oxidative effects induced by a high-calorie diet on the retina of Wistar rats and test the antioxidative effects of carnosine supplementation. METHODS: Wistar rats were randomly divided into the following groups: standard diet (SD), high-calorie diet (HcD), standard diet + carnosine (SD + Car), and high-calorie diet + carnosine (HcD + Car). The body weight, adiposity index, plasma glucose, total lipids, high-density lipoprotein (HDL), low-density lipoprotein (LDL), uric acid, creatinine, and triglycerides of the animals were evaluated. The retinas were analyzed for markers of oxidative stress. Hydrogen peroxide production was assessed by 2',7'-dichlorodihydrofluorescein diacetate (DCF) oxidation. The total glutathione (tGSH), total antioxidant capacity (TAC), protein carbonyl, and sulfhydryl groups of the antioxidant system were analyzed. RESULTS: TAC levels increased in the retinas of the SD + Car group compared to the SD group (p < 0.05) and in the HcD + Car group compared to the HcD group (p < 0.05). The levels of GSH and the GSSH:GSSG ratio were increased in the HcD + Car group compared to the SD + Car group (p < 0.05). An increase in the retinal carbonyl content was observed in the HcD group compared to the SD group (p < 0.05) and in the HcD + Car group compared to the SD + Car group (p < 0.05). A high-calorie diet (HcD) was also associated with a decrease in retinal sulfhydryl-type levels compared to the SD group (p < 0.05). CONCLUSION: The results suggest that feeding a high-calorie diet to rats can promote an increase in carbonyl content and a reduction in sulfhydryl groups in their retinas. The administration of carnosine was not effective in attenuating these oxidative markers. TRIAL REGISTRATION: Animal Ethics Committee of Botucatu Medical School - Certificate number 1292/2019.

The nuclear factor E2-related factor 2 and age-related macular degeneration / O fator 2 relacionado a NF-E2 e a degeneração macular relacionada à idade

ABSTRACT After the discovery of anti-vascular endothelial growth factor agents as treatment of wet age-related macular degeneration, the number of studies with the objective to understand the molecular mechanisms involved in the age-re lated macular degeneration genesis has increased. The importance of the nuclear factor e2-related factor 2 lies in its activation-derived proteins being involved in the maintenance of the redox balance and consequent prevention of degenerative macular disease. This article aims to present the characteristics of nuclear factor e2-related factor 2 and describe the main nuclear factor e2-related factor 2-activated antioxidant enzymes that contribute to the preservation of vision.

RESUMO Após a descoberta do anti fator de crescimento en dotelial vascular no tratamento da degeneração macular relacionada à idade úmida, muitas pesquisas têm sido realizadas com o intuito de elucidar os mecanismos moleculares envolvidos na gênese da degeneração macular relacionada à idade. O fator nuclear eritroide 2 relacionado ao fator 2 destaca-se pelo fato de diversas proteínas, oriundas de sua ativação, estarem envolvidas na manutenção do equilíbrio do estado redox e consequente prevenção da doença macular degenerativa. Este artigo mostra as características do fator nuclear eritroide 2 relacionado ao fator 2 e descreve as principais enzimas antioxidantes originadas da ativação que contribuem para a preservação da visão.

The nuclear factor E2-related factor 2 and age-related macular degeneration.

After the discovery of anti-vascular endothelial growth factor agents as treatment of wet age-related macular degeneration, the number of studies with the objective to understand the molecular mechanisms involved in the age-re lated macular degeneration genesis has increased. The importance of the nuclear factor e2-related factor 2 lies in its activation-derived proteins being involved in the maintenance of the redox balance and consequent prevention of degenerative macular disease. This article aims to present the characteristics of nuclear factor e2-related factor 2 and describe the main nuclear factor e2-related factor 2-activated antioxidant enzymes that contribute to the preservation of vision.

Expression of TNF-α and IL-6 cytokines in the choroid and sclera of hypercholesterolemic rabbits.

PURPOSE: This study aimed to evaluate the expression of the inflammatory cytokines TNF-α and IL-6 in the sclera and choroid of hypercholesterolemic rabbits. METHOD: Twenty-one New Zealand male albino rabbits were divided into two groups: NG and HG. The NG group was fed a standard rabbit diet and the HG group was fed a cholesterol-enriched diet (1%). The serum total cholesterol, triglyceride, HDL cholesterol, and fasting blood glucose levels were determined at the beginning of the experiment and on the day of euthanasia. Euthanasia of animals in the NG and HG groups was performed at the end of the 4th and 8th week, respectively. The eyes were analyzed immunohistochemically using TNF-α and IL-6 antibodies. RESULTS: At the time of euthanasia, the HG group showed a significant increase in total cholesterol and triglyceride when compared with the NG group (p<0.001). When compared with the NG group, there was a significant increase in the expression of TNF-α (p<0.001) and IL-6 (p=0.002) in the choroid and sclera of animals in the HG group. CONCLUSION: This study demonstrates that the hypercholesterolemic diet induces expression of TNF-α and IL-6 in the choroid and sclera of rabbits.

Effect of flaxseed on choroid-sclera complex thickness and on LDL oxidation in the sclera, choroid and retina of diet-induced hypercholesterolaemic rabbits.

The aim of the present study was to evaluate the effect of flaxseed on choroid-sclera complex thickness and on LDL oxidation in the sclera, choroid and retina of diet-induced hypercholesterolaemic rabbits. New Zealand male albino rabbits (n 21) were divided into two groups: group 1 (G1; n 11), fed a hypercholesterolaemic diet, and group 2 (G2; n 10), fed a hypercholesterolaemic diet enriched with flaxseed flour. The serum concentrations of total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol, TAG and fasting blood glucose were determined at the start of the experiment and on the day of killing (8th week). Choroid and sclera samples were subjected to haematoxylin-eosin (HE) staining and histomorphometric and immunohistochemical analyses with the anti-oxidised LDL antibody. Sensory retina samples were subjected to an immunohistochemical analysis with the primary monoclonal nitrotyrosine antibody. At the end of the experiment, a significant increase was observed in TC and LDL-C concentrations in G1 rabbits when compared with G2 rabbits (P= 0·008 and P= 0·02, respectively). HE staining revealed a significant increase in choroid-sclera complex thickness in G1 rabbits when compared with G2 rabbits (P< 0·001). Immunohistochemical analysis of choroid and sclera samples with the anti-oxidised LDL marker revealed a significant increase in immunoreactivity in G1 rabbits when compared with G2 rabbits (P< 0·001). Immunohistochemical analysis of sensory retina samples with the anti-nitrotyrosine marker revealed a significant increase in immunoreactivity in G1 rabbits when compared with G2 rabbits (P= 0·002). Flaxseed reduced the choroid-sclera complex thickness of diet-induced hypercholesterolaemic rabbits and the expression of oxidised LDL in the choroid-sclera complex as well as the expression of nitrotyrosine in the sensory retina.

Aumento da imunorreatividade da molécula de adesão intercelular-1 na esclera e coroide em modelo experimental de hipercolesterolemia / Increased intercellular adhesion molecule-1 immunoreactivity in the sclera-choroid complex in hypercholesterolemia experimental model

Objetivo: O objetivo deste trabalho é avaliar a expressão da molécula de adesão intercelular-1 (ICAM-1) na esclera e coroide de coelhos hipercolesterolêmicos. Métodos: Coelhos New Zealand foram organizados em dois grupos: GN (grupo dieta normal), composto por 8 coelhos (8 olhos), recebeu ração padrão para coelhos, durante 4 semanas; GH (grupo hipercolesterolêmico), composto por 13 coelhos (13 olhos), recebeu dieta rica em colesterol a 1% por 8 semanas. Foi realizada a dosagem sérica de colesterol total, triglicerídeos, HDL colesterol, glicemia de jejum no início do experimento e no momento da eutanásia. Ao final da 4ª semana para o GN e 8ª semana para o GH foi realizada a eutanásia dos animais. Os olhos foram corados com hematoxilina-eosina e submetidos à análise histológica, histomorfométrica e imunohistoquímica com o anticorpo ICAM-1. Resultados: Observou-se significativo aumento do colesterol total e triglicerídeos do GH em relação ao GN (p<0,001). A avaliação histológica com hematoxilina eosina revelou grande quantidade de macrófagos no complexo esclero-coroidal do GH. No GH constatou-se significativo aumento da espessura da esclera e coroide em relação ao GN (p<0,001). Houve significativo aumento da expressão da ICAM-1 na esclera e coroide dos animais do GH em relação ao GN (p<0,001). Conclusão: Este estudo demonstra que a dieta hipercolesterolêmica induz ao aumento da expressão da ICAM-1 na esclera e coroide de coelhos. .

Objective: The aim of this study is to investigate the expression of the intercellular adhesion molecule 1 (ICAM-1) in the sclera and choroid of hypercholesterolemic rabbits Methods: New Zealand rabbits were divided into two groups: the normal diet group (NG), with 8 rabbits (8 eyes), was fed a standard rabbit diet for 4 weeks; the hypercholesterolemic group (HG), with 13 rabbits (13 eyes), was fed a 1% cholesterol- enriched diet for 8 weeks. Total serum cholesterol, triglyceride, HDL cholesterol and fasting blood glucose exams were performed at the start of the experiment and at the euthanasia time. HG and NG animals were euthanized after 8th week and 4th week, respectively. Their eyes were stained with hematoxylin-eosin and underwent histological, histomorphometric and immunohistochemical analyses with ICAM-1 antibody. Results: The diet has induced a significant increase in total cholesterol and triglyceride levels in HG when compared with NG (p<0.001). The histological analysis with hematoxylin-eosin revealed a large number of macrophages in the HG sclera-choroid complex. Moreover, a significant increase in the HG sclera and choroid thickness was observed in relation to NG (p<0.001). There was a significant increase in the ICAM-1 expression in HG sclera and choroid in relation to NG Conclusion: This study has revealed that the hypercholesterolemic diet induces an increase in the ICAM-1 expression in the rabbits’ sclera and choroid. .

Expression of TNF-α and IL-6 cytokines in the choroid and sclera of hypercholesterolemic rabbits / Expressão das citocinas TNF-α and IL-6 na coroide e esclera de coelhos hipercolesterolêmicos

Purpose: This study aimed to evaluate the expression of the inflammatory cytokines TNF-α and IL-6 in the sclera and choroid of hypercholesterolemic rabbits. Method: Twenty-one New Zealand male albino rabbits were divided into two groups: NG and HG. The NG group was fed a standard rabbit diet and the HG group was fed a cholesterol-enriched diet (1%). The serum total cholesterol, triglyceride, HDL cholesterol, and fasting blood glucose levels were determined at the beginning of the experiment and on the day of euthanasia. Euthanasia of animals in the NG and HG groups was performed at the end of the 4th and 8th week, respectively. The eyes were analyzed immunohistochemically using TNF-α and IL-6 antibodies. Results: At the time of euthanasia, the HG group showed a significant increase in total cholesterol and triglyceride when compared with the NG group (p<0.001). When compared with the NG group, there was a significant increase in the expression of TNF-α (p<0.001) and IL-6 (p=0.002) in the choroid and sclera of animals in the HG group. Conclusion: This study demonstrates that the hypercholesterolemic diet induces expression of TNF-α and IL-6 in the choroid and sclera of rabbits. .

Objetivo: Avaliar a expressão das citocinas inflamatórias TNF-α e IL-6 na esclera e coroide de coelhos hipercolesterolêmicos. Método: Coelhos New Zealand foram organizados em dois grupos: GN recebeu ração padrão para coelhos; GH recebeu dieta rica em colesterol a 1%. Foi realizada a dosagem sérica de colesterol total, triglicerídeos, HDL colesterol, glicemia de jejum no início do experimento e no momento da eutanásia. Ao final da 4ª semana para o GN e 8ª semana para o GH foi realizada a eutanásia dos animais. Os olhos foram submetidos à análise imuno-histoquímica com os anticorpos TNF-α e IL-6. Resultados: O GH manifestou significativo aumento do colesterol total e triglicerídeos em relação ao GN (p<0,001). Houve significativo aumento da expressão da TNF-α (p<0,001) e da IL-6 (p=0,002) na coroide e esclera dos animais do GH em relação ao GN. Conclusão: Este estudo demonstra que a dieta hipercolesterolêmica induz ao aumento da expressão das citocinas TNF-α e IL-6 na coroide e esclera de coelhos. .

Effect of candesartan on the expression of sclera-choroidal intercellular adhesion molecule-1 in hypercholesterolemic models.

OBJECTIVE: To evaluate the effect of blocking the angiotensin II AT-1 receptor by the systemic administration of candesartan on the expression of intercellular adhesion molecule-1 in the sclera and choroid of hypercholesterolemic rabbits. METHODS: New Zealand rabbits were divided into 3 groups, as follows: GI, which was fed a rabbit standard diet; GII, which was fed a hypercholesterolemic diet; and GIII, which received hypercholesterolemic diet plus candesartan. Samples of the rabbits' sclera and choroid were then studied by hematoxylin-eosin staining and histomorphometric and immunohistochemical analyses for intercellular adhesion molecule-1 expression. RESULTS: Histological analysis of hematoxylin- and eosin-stained sclera and choroid revealed that macrophages were rarely present in GI, and GII had significantly increased macrophage numbers compared to GIII. Moreover, in GII, the sclera and choroid morphometry showed a significant increase in thickness in comparison to GI and GIII. GIII presented a significant increase in thickness in relation to GI. Sclera and choroid immunohistochemical analysis for intercellular adhesion molecule-1 expression revealed a significant increase in immunoreactivity in GII in relation to GI and GIII. GIII showed a significant increase in immunoreactivity in relation to GI. CONCLUSION: Candesartan reduced the expression of intercellular adhesion molecule-1 and consequently macrophage accumulation in the sclera and choroid of hypercholesterolemic rabbits.

Effect of candesartan on the expression of sclera-choroidal intercellular adhesion molecule-1 in hypercholesterolemic models

OBJECTIVE: To evaluate the effect of blocking the angiotensin II AT-1 receptor by the systemic administration of candesartan on the expression of intercellular adhesion molecule-1 in the sclera and choroid of hypercholesterolemic rabbits. METHODS: New Zealand rabbits were divided into 3 groups, as follows: GI, which was fed a rabbit standard diet; GII, which was fed a hypercholesterolemic diet; and GIII, which received hypercholesterolemic diet plus candesartan. Samples of the rabbits' sclera and choroid were then studied by hematoxylin-eosin staining and histomorphometric and immunohistochemical analyses for intercellular adhesion molecule-1 expression. RESULTS: Histological analysis of hematoxylin- and eosin-stained sclera and choroid revealed that macrophages were rarely present in GI, and GII had significantly increased macrophage numbers compared to GIII. Moreover, in GII, the sclera and choroid morphometry showed a significant increase in thickness in comparison to GI and GIII. GIII presented a significant increase in thickness in relation to GI. Sclera and choroid immunohistochemical analysis for intercellular adhesion molecule-1 expression revealed a significant increase in immunoreactivity in GII in relation to GI and GIII. GIII showed a significant increase in immunoreactivity in relation to GI. CONCLUSION: Candesartan reduced the expression of intercellular adhesion molecule-1 and consequently macrophage accumulation in the sclera and choroid of hypercholesterolemic rabbits. .

[Increased VEGFR-1 immunoreactivity in the choroid-scleral complex in hypercholesterolemia experimental model]. / Aumento da imunorreatividade ao VEGFR-1 no complexo coroido-escleral em modelo experimental de hipercolesterolemia.

PURPOSE: The aim of this study is to investigate the expression of vascular endothelial growth factor (VEGF) in the choroid and sclera using hypercholesterolemia experimental model. METHODS: New Zealand rabbits were divided into two groups: 8 rabbits (8 eyes), in the normal diet group (NG), were fed by a standard diet for 4 weeks; and 13 rabbits (13 eyes), in the hypercholesterolemic group (HG), were fed by a 1% cholesterol-enriched diet for 8 weeks. Total serum cholesterol, triglyceride, HDL cholesterol and fasting blood glucose exams were performed at the initiation of the experiment and at the euthanasia time. After hypercholesterolemic group 8th week and NG 4th week, animals were euthanized and their eyes underwent immunohistochemical analysis with the RAM-11 and VEGFR-1). RESULTS: The diet has induced a significant increase in total cholesterol and triglyceride levels in HG when compared with NG (p<0.001). There was a significant increase in the RAM-11 and VEGFR-1 expressions in hypercholesterolemic group choroid and sclera in relation to NG (p<0,001). CONCLUSION: This study has revealed that the hypercholesterolemic diet in rabbits induces an increase in the macrophage concentration and immunoreactivity to VEGFR-1 in the choroid and sclera, resembling human age-related macular degeneration (ARMD).

Effect of olmesartan on leukocyte recruitment in choroid-sclera complex in hypercholesterolemia model.

PURPOSE: Demonstrate that the blockade of angiotensin II AT-1 receptors, through the systemic administration of olmesartan, can reduce the MCP-1 expression and the resulting macrophage accumulation in the choroid and sclera of hypercholesterolemic rabbits. METHODS: Thirty-two New Zealand rabbits were divided into 3 groups: group I (GI) was fed a standard rabbit diet; group II (GII) was fed a hypercholesterolemic diet; and group III (GIII) was fed a hypercholesterolemic diet plus olmesartan. Serum levels of total cholesterol, triglyceride, HDL cholesterol, and blood glucose were determined in fasting rabbits at the beginning of the experiment and on the day of euthanasia. The choroid and sclera were submitted to morphometric analysis as well as immunohistochemical analysis with MCP-1 and RAM-11 (macrophage marker) antibodies. RESULTS: No abnormality was detected in GI. Group II and III had significant increases in choroid-sclera complex thicknesses when compared with group I (P<0.001). GII showed a significant increase in immunoreactivity for MCP-1 in relation to GI (P=0.001) and GIII (P=0.004). GII showed a significant increase in immunoreactivity for RAM-11 of the choroid-sclera complex in relation to GI (P<0.001) and GIII (P=0.034). A significant increase in immunoreactivity for RAM-11 was observed in GIII in relation to GI (P=0.008). CONCLUSION: Olmesartan reduced the MCP-1 expression and the resultant macrophage accumulation in the choroid-sclera complex of hypercholesterolemic rabbits.

Aumento da imunorreatividade ao VEGFR-1 no complexo coroido-escleral em modelo experimental de hipercolesterolemia / Increased VEGFR-1 immunoreactivity in the choroid-scleral complex in hypercholesterolemia experimental model

OBJETIVO: O objetivo deste trabalho é investigar a expressão do fator de crescimento vascular endotelial (VEGF) na coroide e esclera, utilizando um modelo experimental de hipercolesterolemia. MÉTODO: Coelhos New Zealand foram organizados em dois grupos: O grupo dieta normal (GN), composto por 8 coelhos (8 olhos), recebeu ração padrão para coelhos, durante 4 semanas; e o grupo hipercolesterolêmico (GH), composto por 13 coelhos (13 olhos), recebeu dieta rica em colesterol a 1% por 8 semanas. Foi realizada a dosagem sérica de colesterol total, triglicerídeos, HDL colesterol, glicemia de jejum no início do experimento e no momento da eutanásia. Ao final da 8ª semana para o GH e 4ª semana para o GN foi realizada a eutanásia dos animais e os olhos foram submetidos à análise imuno-histoquímica com os anticorpos RAM-11 e VEGFR-1. RESULTADOS: Observou-se significativo aumento do colesterol total e triglicerídeos do GH em relação ao GN (p<0,001). Houve significativo aumento da expressão da RAM-11 e VEGFR-1 na coroide e esclera dos animais do GH em relação ao GN (p<0,001). CONCLUSÃO: Este estudo demonstra que a dieta hipercolesterolêmica em coelhos induz ao aumento da concentração de macrófagos e da imunorreatividade ao VEGFR-1 na coroide e esclera, expressando similaridade com a degeneração macular relacionada à idade (DMRI) humana.

PURPOSE: The aim of this study is to investigate the expression of vascular endothelial growth factor (VEGF) in the choroid and sclera using hypercholesterolemia experimental model. METHODS: New Zealand rabbits were divided into two groups: 8 rabbits (8 eyes), in the normal diet group (NG), were fed by a standard diet for 4 weeks; and 13 rabbits (13 eyes), in the hypercholesterolemic group (HG), were fed by a 1% cholesterol-enriched diet for 8 weeks. Total serum cholesterol, triglyceride, HDL cholesterol and fasting blood glucose exams were performed at the initiation of the experiment and at the euthanasia time. After hypercholesterolemic group 8th week and NG 4th week, animals were euthanized and their eyes underwent immunohistochemical analysis with the RAM-11 and VEGFR-1). RESULTS: The diet has induced a significant increase in total cholesterol and triglyceride levels in HG when compared with NG (p<0.001). There was a significant increase in the RAM-11 and VEGFR-1 expressions in hypercholesterolemic group choroid and sclera in relation to NG (p<0,001). CONCLUSION: This study has revealed that the hypercholesterolemic diet in rabbits induces an increase in the macrophage concentration and immunoreactivity to VEGFR-1 in the choroid and sclera, resembling human age-related macular degeneration (ARMD).

[Increase of choroidal and scleral MCP-1 expression in hypercholesterolemia experimental model]. / Aumento da expressão do MCP-1 coroidal e escleral em modelo experimental de hipercolesterolemia.

PURPOSE: The aim of this study is to experientially demonstrate that a cholesterol-enriched diet induces an increase in the MCP-1 expression in the choroid and sclera. METHOD: New Zealand rabbits were divided into two groups: GN (normal diet group) of 8 rabbits (8 eyes) was fed a standard rabbit diet for 4 weeks; GH (hypercholesterolemic group) of 13 rabbits (13 eyes) was fed a 1% cholesterol enriched diet for 8 weeks. Total serum cholesterol, triglyceride, HDL cholesterol and fasting blood glucose exams were performed at the start of the experiment and at the euthanasia time. After GH 8th week and GN 4th week animals were euthanized and their eyes underwent immunohistochemical analysis with the anti-MCP-1 antibody. RESULTS: The diet has induced a significant increase in GH total cholesterol and triglyceride levels when compared with NG (p<0.001). There was a significant increase in the MCP-1 expression in GH choroid and sclera in relation to GN (p<0.001). CONCLUSION: This study has revealed that the hypercholesterolemic diet in rabbits induces an increase in the MCP-1 expression in the choroid and sclera.

Aumento da expressão do MCP-1 coroidal e escleral em modelo experimental de hipercolesterolemia / Increase of choroidal and scleral MCP-1 expression in hypercholesterolemia experimental model

OBJETIVO: O objetivo deste trabalho é demonstrar experimentalmente que a dieta rica em colesterol provoca aumento da expressão da MCP-1 na coroide e esclera. MÉTODO: Coelhos New Zealand foram organizados em dois grupos: GN (grupo dieta normal), composto por 8 coelhos (8 olhos), recebeu ração padrão para coelhos, durante 4 semanas; GH (grupo hipercolesterolêmico), composto por 13 coelhos (13 olhos), recebeu dieta rica em colesterol a 1% por 8 semanas. Foi realizada a dosagem sérica de colesterol total, triglicerídeos, HDL colesterol, glicemia de jejum no início do experimento e no momento da eutanásia. Ao final da 8ª semana para o GH e 4ª semana para o GN foi realizada a eutanásia dos animais e os olhos foram submetidos à análise imuno-histoquímica com o anticorpo anti-MCP-1. RESULTADOS: A dieta provocou significativo aumento do colesterol total e triglicerídeos do GH em relação ao GN (p<0,001). Houve significativo aumento da expressão da MCP-1 na coroide e esclera dos animais do GH em relação ao GN (p<0,001). CONCLUSÃO: Este estudo demonstrou que a dieta hipercolesterolêmica em coelhos induz ao aumento da expressão do MCP-1 na coroide e esclera.

PURPOSE: The aim of this study is to experientially demonstrate that a cholesterol-enriched diet induces an increase in the MCP-1 expression in the choroid and sclera. METHOD: New Zealand rabbits were divided into two groups: GN (normal diet group) of 8 rabbits (8 eyes) was fed a standard rabbit diet for 4 weeks; GH (hypercholesterolemic group) of 13 rabbits (13 eyes) was fed a 1% cholesterol enriched diet for 8 weeks. Total serum cholesterol, triglyceride, HDL cholesterol and fasting blood glucose exams were performed at the start of the experiment and at the euthanasia time. After GH 8th week and GN 4th week animals were euthanized and their eyes underwent immunohistochemical analysis with the anti-MCP-1 antibody. RESULTS: The diet has induced a significant increase in GH total cholesterol and triglyceride levels when compared with NG (p<0.001). There was a significant increase in the MCP-1 expression in GH choroid and sclera in relation to GN (p<0.001). CONCLUSION: This study has revealed that the hypercholesterolemic diet in rabbits induces an increase in the MCP-1 expression in the choroid and sclera.

Sclerochorioretinal abnormalities in hypercholesterolemic rabbits treated with rosiglitazone.

BACKGROUND AND OBJECTIVE: To evaluate early retinal, choroidal, and scleral abnormalities induced by a hypercholesterolemic diet and the prevention of these abnormalities after oral administration of rosiglitazone in rabbits. MATERIALS AND METHODS: Fifty-four New Zealand rabbits were divided into four study groups: control group, normal diet; group 1, hypercholesterolemic diet; group 2, hypercholesterolemic diet associated with daily administration of 3 mg of rosiglitazone from day 14 after beginning the diet; and group 3, hypercholesterolemic diet associated with daily administration of 3 mg of rosiglitazone since the beginning of the experiment. Sclera and choroid underwent histologic and histomorphometric analyses. Retina underwent immunohistochemical analysis with anti-calretinin and anti-glial fibrillary acidic protein (GFAP) antibodies. RESULTS: No abnormalities were observed in the control group. Group 1 had significant increases in scleral and choroidal thicknesses compared with the control group (P < .01) and group 3 (P < .05). Group 1 presented significant increases in immunoreactivity (P < .001) to the anti-calretinin antibody compared with the other groups. Groups 2 and 3 had significant (P < .002) increases in calretinin immunoreactivity compared with the control group. GFAP was negative in all groups. CONCLUSION: The hypercholesterolemic diet induced early retinal, choroidal, and scleral abnormalities. Rosiglitazone preserved the structural anatomy.

Evaluation of early abnormalities of the sensory retina in a hypercholesterolemia experimental model: an immunohistochemical study / Avaliação das anormalidades precoces da retina sensorial em modelo experimental de hipercolesterolemia: estudo imunohistoquímico

PURPOSE: The aim of this study is to demonstrate the early changes of the sensory retina induced by hypercholesterolemia in an experimental model. METHODS: New Zealand rabbits were divided into two groups: CG (Control Group) was fed a normal diet for 6 weeks. G1 was initially fed a 1 percent cholesterol diet for two weeks and from the 14th day on a 0.5 percent cholesterol diet until the 42nd day. The eyes underwent an immunohistochemical analysis with monoclonal antibodies anti-calretinin and anti-glial fibrillary acidic protein (GFAP). RESULTS: G1 cells and cell elements presented significant immunoreactivity to anti-calretinin. No immunoreactivity to anti-glial fibrillary acidic protein was observed in both groups. CONCLUSION: This study has shown that a hypercholesterolemic diet may induce early changes in the sensory retina in rabbits. The anti-calretinin monoclonal antibody was able to reveal calcium accumulation inside the nerve cells.

OBJETIVO: O objetivo deste estudo é demonstrar experimentalmente as alterações precoces da retina sensorial induzidas pela hipercolesterolemia. MÉTODOS: Coelhos New Zealand foram organizados em dois grupos: GC (grupo controle), composto por 6 coelhos (6 olhos), recebeu dieta normal por 6 semanas; G1, composto por 12 coelhos (12 olhos), tratado previamente com ração colesterol a 1 por cento (Sigma-Aldrich) por 2 semanas e a partir do 14º dia com ração colesterol a 0,5 por cento (Sigma-Aldrich). Os olhos foram submetidos à análise imunohistoquímica com os anticorpos monoclonais anticalretinina e anti-glial fibrillary acidic protein (GFAP). RESULTADOS: G1 apresentou maior número de células e elementos celulares imunoreativos a anticalretinina que o GC, com relevância estatística. GFAP foi negativo em ambos os grupos. CONCLUSÃO: Este estudo demonstrou que a dieta hipercolesterolêmica pode induzir alterações precoces na retina sensorial em coelhos. O anticorpo monoclonal anticalretinina foi capaz de revelar o acúmulo de cálcio dentro das células neuronais retiniana.

[Modifiable risk factors for age-related macular degeneration]. / Fatores modificáveis da degeneração macular relacionada à idade.

The authors present the main modifiable risk factors that may trigger and/or worsen age-related macular degeneration. Mechanisms of action related to these factors as well as preventive measures and intervention effectiveness are discussed.

Fatores modificáveis da degeneração macular relacionada à idade / Modifiable risk factors for age-related macular degeneration

Os autores apresentam os principais fatores modificáveis considerados de risco para o desencadeamento e/ou agravamento da degeneração macular relacionada com a idade. São abordados os mecanismos de ação destes fatores, assim como medidas preventivas e eficácia de eventuais intervenções.

The authors present the main modifiable risk factors that may trigger and/or worsen age-related macular degeneration. Mechanisms of action related to these factors as well as preventive measures and intervention effectiveness are discussed.

[Evaluation of choroid and sclera early alterations in hypercholesterolemic rabbits: histologic and histomorphometric study]. / Avaliação das alterações precoces na coróide e esclera ocorridas em coelhos hipercolesterolêmicos: estudo histológico e histomorfométrico.

PURPOSE: To demonstrate experimentally, by means of histological and histomorphometric examinations, the sclera and choroid degenerative alterations, which take place at an early stage due to a hypercholesterolemic diet. METHODS: New Zealand rabbits were divided into two groups: CG (control group) of 6 rabbits (6 eyes) received a regular diet for 6 weeks; G1, of 12 rabbits (12 eyes), was first fed a 1% cholesterol diet (Sigma-Aldrich) for 2 weeks and then from the 14th day on a 0.5% cholesterol diet (Sigma-Aldrich). The eyes underwent a histological analysis, stained with hematoxiline-eosine, and a morphometric examination. The histomorphometric analysis was performed in the posterior region, adjacent to the optic disk, and in the peripheral region. RESULTS: The CG presented a mean sclera and choroid thickness of 228.61 +/- 31.71 micrometers in the peripheral region, while the thickness in the posterior region was approximately 246.07 +/- 25.66 micrometers. In G1, these values were 303.56 +/- 44.21 micrometers in the peripheral region and 295.59 +/- 62.59 in the posterior region. There was a statistically significant difference in the sclera and choroid thickness between the groups in the peripheral region (p<0.001); however, this difference did not occur in the posterior region (p=0.250). The large number of histiocytes and collagen fibers accounted for the increase of G1 wall thickness in relation to CG. CONCLUSION: This study demonstrated that the hypercholesterolemic diet in rabbits induces a fast increase in the choroid and sclera thickness, mainly due to the increase in the number of histiocytes and collagen fibers.

Avaliação das alterações precoces na coróide e esclera ocorridas em coelhos hipercolesterolêmicos: estudo histológico e histomorfométrico / Evaluation of choroid and sclera early alterations in hypercholesterolemic rabbits: histologic and histomorphometric study

OBJETIVO: Demonstrar experimentalmente, através de exames histológicos e histomorfométricos, as alterações degenerativas da esclera e coróide desencadeadas precocemente pela dieta hipercolesterolêmica. MÉTODOS: Coelhos New Zealand foram organizados em dois grupos: GC (grupo controle), composto por 6 coelhos (6 olhos), recebeu dieta normal por 6 semanas; G1, composto por 12 coelhos (12 olhos), tratado previamente com ração colesterol a 1 por cento (Sigma-Aldrich) por 2 semanas e a partir do 14º dia com ração colesterol a 0,5 por cento (Sigma-Aldrich). Os olhos foram submetidos à análise histológica, avaliados com corante de hematoxilina-eosina e ao exame morfométrico. A análise histomorfométrica foi realizada no setor posterior, adjacente ao disco óptico, e na periferia. RESULTADOS: O GC apresentou espessura média da esclera e coróide na periferia de 228,61 ± 31,71 micrômetros, enquanto na região posterior de aproximadamente 246,07 ± 25,66 micrômetros. No G1, observou-se espessura média da esclera e coróide na periferia de aproximadamente 303,56 ± 44,21 micrômetros, enquanto na região posterior de aproximadamente 295,59 ± 62,59. Houve diferença estatisticamente significativa da espessura da esclera e coróide entre os grupos na região periférica (p<0,001), não ocorrendo o mesmo no setor posterior (p=0,250). O aumento da espessura da parede de G1 em relação ao GC deve-se principalmente à quantidade elevada de histiócitos e fibras colágenas. CONCLUSÃO: Este estudo demonstrou que a dieta hipercolesterolêmica em coelhos induz rapidamente aumento da espessura da coróide e esclera, principalmente à custa de histiócitos e fibras colágenas.

PURPOSE: To demonstrate experimentally, by means of histological and histomorphometric examinations, the sclera and choroid degenerative alterations, which take place at an early stage due to a hypercholesterolemic diet. METHODS: New Zealand rabbits were divided into two groups: CG (control group) of 6 rabbits (6 eyes) received a regular diet for 6 weeks; G1, of 12 rabbits (12 eyes), was first fed a 1 percent cholesterol diet (Sigma-Aldrich) for 2 weeks and then from the 14th day on a 0.5 percent cholesterol diet (Sigma-Aldrich). The eyes underwent a histological analysis, stained with hematoxiline-eosine, and a morphometric examination. The histomorphometric analysis was performed in the posterior region, adjacent to the optic disk, and in the peripheral region. RESULTS: The CG presented a mean sclera and choroid thickness of 228.61 ± 31.71 micrometers in the peripheral region, while the thickness in the posterior region was approximately 246.07 ± 25.66 micrometers. In G1, these values were 303.56 ± 44.21 micrometers in the peripheral region and 295.59 ± 62.59 in the posterior region. There was a statistically significant difference in the sclera and choroid thickness between the groups in the peripheral region (p<0.001); however, this difference did not occur in the posterior region (p=0.250). The large number of histiocytes and collagen fibers accounted for the increase of G1 wall thickness in relation to CG. CONCLUSION: This study demonstrated that the hypercholesterolemic diet in rabbits induces a fast increase in the choroid and sclera thickness, mainly due to the increase in the number of histiocytes and collagen fibers.