ABSTRACT
Background: Chronic glucocorticoid treatment induces the development of renal injury via mineralocorticoid receptor (MR) activation in bilaterally adrenalectomized rats. It has been hypothesized that glucocorticoid contributes to the development of left ventricular (LV) remodeling through MR activation in bilaterally adrenalectomized rats (ADX).Methods: ADX rats were maintained with 1%NaCl in drinking water and randomly treated as follows for 8 weeks: vehicle (n=7), bilateral adrenalectomy (ADX) + hydrocortisone (HYDRO) (5 mg/kg/day, subcutaneous, n=7), and ADX + HYDRO + eplerenone (0.125% in chow; approximately 75 mg/kg/day, n=7). An osmotic minipump was implanted subcutaneously for continuous infusion of HYDRO. Results: As compared with control vehicletreated uninephrectomized rats, ADX+HYDRO treatment for 8 weeks significantly increased systolic blood pressure, LV weight, collagen content and mRNA levels of atrial natriuretic peptide, brain natriuretic peptide, and collagen type 1 and III. These changes were associated with increase in LV thiobarbituric acid reactive substances content, dihydroethidium fluorescence and mRNA levels of NADPH oxidase subunits. Treatment with a selective MR antagonist, eplerenone significantly attenuated HYDRO induced changes in LV parameters. HYDRO-induced increases in mRNA and protein levels of serum and glucocorticoid-regulated kinases 1 were prevented by eplerenone. Conclusion: These data suggest that chronic glucocorticoid treatment induces LV tissue remodeling through MR dependent mechanism in bilateral adrenalectomized rats.
ABSTRACT
The aim of this study was to detect arsenic concentrations in feed, well-water for drinking, eggs, and excreta of laying hens in arsenic-prone areas of Bangladesh and to assess the effect of arsenic-containing feed and well-water on the accumulation of arsenic in eggs and excreta of the same subject. One egg from each laying hen (n=248) and its excreta, feed, and well-water for drinking were collected. Total arsenic concentrations were determined by atomic absorption spectrophotometer, coupled with hydride generator. Effects of arsenic-containing feed and drinking-water on the accumulation of arsenic in eggs and excreta were analyzed by multivariate regression model, using Stata software. Mean arsenic concentrations in drinkingwater, feed (dry weight [DW]), egg (wet weight [WW]), and excreta (DW) of hens were 77.3, 176.6, 19.2, and 1,439.9 ppb respectively. Significant (p<0.01) positive correlations were found between the arsenic contents in eggs and drinking-water (r=0.602), drinking-water and excreta (r=0.716), feed and excreta (r=0.402) as well as between the arsenic content in eggs and the age of the layer (r=0.243). On an average, 55% and 82% of the total variation in arsenic contents of eggs and excreta respectively could be attributed to the variation in the geographic area, age, feed type, and arsenic contents of drinking-water and feed. For each week’s increase in age of hens, arsenic content in eggs increased by 0.94%. For every 1% elevation of arsenic in drinking-water, arsenic in eggs and excreta increased by 0.41% and 0.44% respectively whereas for a 1% rise of arsenic in feed, arsenic in eggs and excreta increased by 0.40% and 0.52% respectively. These results provide evidence that, although high arsenic level prevails in well-water for drinking in Bangladesh, the arsenic shows low biological transmission capability from body to eggs and, thus, the value was below the maximum tolerable limit for humans. However, arsenic in drinking-water and/or feed makes a significant contribution to the arsenic accumulations in eggs and excreta of laying hens.
ABSTRACT
The hydroethanolic extract of the flowering tops of Anthocephalus cadamba (Roxb.) Miq., Rubiaceae, a Bangladeshi medicinal plant, was studied for its potential hypoglycemic effect and antioxidant property in alloxan-induced diabetic rats. The extract induced significant reduction in serum glucose, and transaminases, e.g. aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatases (ALP), activities. Significant changes in the thiobarbituric acid reactive substances (TBARS), peroxidase and catalase levels during the experimental period were also observed. The results established that the hydroethanolic extract of the flowering tops of A. cadamba possesses hypoglycemic property and is able to protect liver and brain from oxidative damages caused by diabetes.