Green tea (GT), through its antioxidant properties, may be useful to treat or prevent human diseases. Because several lines of evidence suggest that oxidative stress contributes to the pathogenesis of diabetic nephropathy, we tested the hypothesis that GT prevents diabetes and hypertension-related renal oxidative stress, attenuating renal injury. Spontaneously hypertensive rats (SHR) with streptozotocin-induced diabetes and nondiabetic SHR were treated daily with tap water or freshly prepared GT (13.3 g/L). After 12 wk, the systolic blood pressure did not differ between treated and untreated nondiabetic or diabetic rats. However, body weight was less (P < 0.05) and glycemia was greater in diabetic SHR rats than in nondiabetic rats. Renal oxidative stress variables such as 8-hydroxy-2'-deoxyguanosine (8-OHdG) and nitrotyrosine expression, NADPH oxidase-dependent superoxide generation, and the expression of renal cortex Nox4 were greater (P < 0.05) in diabetic rats that received water (DW) than in nondiabetic rats that received water (CW). The 8-OHdG and NADPH oxidase-dependent superoxide generation were significantly less in rats treated with GT. Nitrotyrosine and Nox4 expression were significantly less in diabetic rats that received GT (DGT) than in DW. Likewise, the indices of renal injury, albuminuria, and renal expression of collagen IV were significantly greater in DW than in CW. These differences were significantly less in DGT than in DW. GT reestablished the redox state and reduced the indicators of nephropathy without altering glycemia and blood pressure levels in diabetic SHR. These findings suggest that the consumption of GT may ameliorate nephropathy in diabetic hypertensive patients.
Aims: The combination of hypertension and diabetes exacerbates renal oxidative stress. The aim of the present study was therefore to evaluate the pro-oxidant and antioxidant mechanisms responsible for the induction of renal oxidative stress in the presence of hypertension and diabetes mellitus. Methods: Diabetes was induced in spontaneously hypertensive rats (SHR) and their genetically normotensive control Wistar-Kyoto (WKY) rats by streptozotocin at 12 weeks of age. After 10 days, pro-oxidant, antioxidant and oxidative stress parameters were evaluated in the renal tissue. Results: NADPH oxidase-dependent superoxide generation in the renal cortex was significantly elevated in WKY and SHR diabetic (D) groups compared to the respective control (C) groups (p < 0.005, n = 5). However, the highest level of superoxide generation was observed in the SHR-D group compared to all other groups. The expression of the gp91phox subunit of NADPH oxidase was significantly elevated in the SHR-D (p < 0.05, n = 5), but not in the WKY-D group, compared to the respective control groups. The renal cortical extracellular-superoxide dismutase level was found to be markedly decreased in the SHR groups compared to the WKY groups (p < 0.05, n = 5). The antioxidant glutathione level was found to be lower in the SHR-D (p = 0.03, n = 15), but not in the WKY-D group, compared to the respective control groups. Finally, nitrotyrosine and 8-hydroxy-2′-deoxyguanosine, markers of oxidative stress, were found to be similar in the kidneys of WKY-C and WKY-D, but were elevated in the SHR-D compared to the SHR-C group. Conclusion: We therefore conclude that hypertension increases pro-oxidant generation and decreases antioxidant defense, and thereby induces renal oxidative stress in early diabetes.
O entendimento sobre a vulnerabilidade ambiental constitui meio extremante importante para a instituição de políticas públicas de planejamento territorial e para a adoção de práticas de manejo para o correto uso e ocupação da terra, possibilitando a minimização dos impactos e desastres ambientais. Dessa forma, o objetivo desse artigo compreende o mapeamento da vulnerabilidade ambiental da Sub-bacia dos Rios Mogi Guaçu e Pardo, Sul de Minas Gerais. Os métodos utilizados abrangeram interpolações geoestatísticas, processamento digital de imagens e álgebra de mapas. A vulnerabilidade da unidade de paisagem (vulnerabilidade ambiental) foi obtida pela média das variáveis vulnerabilidade geológica, geomorfológica, pedológica, climatológica e de uso e ocupação da terra, segundo metodologia recomendada pela literatura especializada. A Sub-bacia dos Rios Mogi Guaçu e Pardo apresenta baixo grau de vulnerabilidade (grau 1,0) em praticamente metade do seu território (48%), indicando o predomínio dos processos pedogenéticos sobre os processos morfogenéticos (categoria morfodinâmica de estabilidade). Portanto, na busca por uma política preservacionista e conservacionista para a sub-bacia, necessário se faz adotar boas práticas de manejo, para que as áreas com grau 2,0 (equilíbrio entre pedogênese e morfogênese), correspondentes à maior parte do território (52%) não se tornem instáveis, com predomínio da morfogênese, prevalecente os processos erosivos.Palavras-chave: Álgebra de mapas, desestabilização da paisagem, planejamento territorial, sistemas ambientais. Environmental Vulnerability of the Sub-Basin of the Mogi Guaçu and Pardo Rivers - MG ABSTRACTUnderstanding environmental vulnerability is an extremely important means for the establishment of public policies for territorial planning and for the adoption of management practices for the correct use and occupation of land, enabling the minimization of environmental impacts and disasters. Thus, the objective of this article comprises the mapping of the environmental vulnerability of the Sub-basin of the Mogi Guaçu and Pardo Rivers, southern Minas Gerais. The methods used included geostatistical interpolations, digital image processing and map algebra. The vulnerability of the landscape unit (environmental vulnerability) was obtained by the average of the geological, geomorphological, pedological, climatological and land use and occupation vulnerability variables, according to the methodology recommended by the specialized literature. The Sub-basin of the Mogi Guaçu and Pardo Rivers presents a low degree of vulnerability (degree 1.0) in practically half of its territory (48%), indicating the predominance of pedogenetic processes over morphogenetic processes (morphodynamic stability category). Therefore, in the search for a preservation and conservation policy for the sub-basin, it is necessary to adopt good management practices, so that areas with grade 2.0 (balance between pedogenesis and morphogenesis), corresponding to most of the territory (52 %) do not become unstable, with a predominance of morphogenesis, prevailing erosive processes.Keywords: Map algebra, landscape destabilization, territorial planning, environmental systems
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