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Biomedical subjects

P Mayoral

Publications and source records attributed to P Mayoral.

7 recordsLinked to original sources
PubMed2006

Protective effect of quercetin on experimental chronic cadmium nephrotoxicity in rats is based on its antioxidant properties.

Oxidative stress can play a key role in Cd-induced dysfunctions. Quercetin is a potent oxygen free radicals scavenger and a metal chelator. Our aim was to study the effect of quercetin on Cd-induced kidney damage and oxidative stress as well as its mechanism of action. Wistar rats were distributed in four experimental groups: control rats; Cd; quercetin and Cd+quercetin. Renal toxicity was evaluated by measuring urinary excretion of proteins, albumin, glucose and enzymes markers of tubular necrosis, as well as plasma concentration of creatinine. Plasma TBARS concentration and activity of antioxidant enzymes in kidney were also measured. Renal cell damage was assessed by electron microscopy. Animals that received both Cd and quercetin showed a better renal function than those receiving Cd alone. Cd-induced tubular lesions were markedly reduced in rats that also received quercetin. Cd-induced increase in plasma TBARS was prevented by the administration of quercetin. Total plasma antioxidants and renal superoxide dismutase and glutathione-reductase activities were higher in the group that received Cd and quercetin than in rats that received Cd alone. Quercetin administration does not modify the renal content or the urinary excretion of Cd. In conclusion, quercetin treatment prevents renal tubular damage and increased oxidative stress induced by chronic Cd administration, most probably throughout its antioxidant properties.

Animals↗
PubMed2003

Effect of ham protein substitution on oxidative stress in older adults.

Mediterranean diet has been related to a low risk of coronary hearth disease. In the present study, we have evaluated the effect of substituting 120 g of meat by 120 g of acorn-fed Iberian ham (one of the meat components of the Mediterranean diet) on body weight, blood pressure (MAP), plasma lipids and oxidant-antioxidant equilibrium in 13 males and 8 females with an average age of 71. Study was performed in three periods: basal diet evaluations (BD1), ham diet for 6 weeks (HD), and basal diet again for 6 weeks (BD2). MAP significantly diminished from 96 mmHg in BD1 to 89 mmHg after HD. After BD2, MAP remained in the same value. Plasma total antioxidant substances increased from 0.791 mmol/L in BD1, to 1.525 in HD, and to 1.213 in BD2. Glutathione reductase significantly increased from 49.5 U/L in BD1 to 57 in HD and decreased to 49.2 in BD2. Glutathione peroxidase rose from 33 U/gHb in BD1 to 72 in HD and decreased to 52 in BD2. Superoxide dismutase increased from 401 U/gHb in BD1 to 723 in HD and decreased to 433 in BD2. Plasma thiobarbituric acid reacting substances (TBARS) fall from 1.65 mmol/l in BD1 to 1.38 in HD and to 1.47 in BD2. TBARS in erythrocyte membranes also diminished but only in BD2. It can be concluded that including acorn-fed Iberian ham in the diet increased the antioxidant substances and decrease lipid peroxidation, with its subsequent beneficial effects on the atherogenic risk factors.

Aged↗
PubMed1999

Effects of chronic nitric oxide activation or inhibition on early hepatic fibrosis in rats with bile duct ligation.

Hepatic fibrosis or increased liver collagen contents drive functional abnormalities that, when extensive, may be life threatening. The purpose of this study was to assess the effects of the chronic stimulation or inhibition of nitric oxide synthesis in rats with hepatic fibrosis induced by permanent common bile duct ligation (3 weeks) and the role of expression of the different nitric oxide synthase isoforms. Bile duct ligation led to an important accumulation of collagen in the hepatic parenchyma, as shown both histologically and by the hydroxyproline contents of livers. Bilirubin and serum enzyme activities (measured as markers of cholestasis) increased several-fold after bile duct ligation. The area of fibrotic tissue, liver hydroxyproline content and serum markers of cholestasis were clearly related in obstructed rats. The absence of modifications in haemodynamic parameters excludes circulatory changes from being responsible for the development of liver alterations. In animals treated with NG-nitro-L-arginine methyl ester (L-NAME) the area of fibrosis was similar to that of untreated animals, the signs of cholestasis and cellular injury being more evident. In rats treated with L-arginine the area of fibrosis was almost three times larger than that found in bile duct ligated rats and in L-NAME-treated bile duct ligated rats, although the observed biochemical changes were similar to those seen in rats treated with L-NAME. Our results with inducible nitric oxide synthase, obtained by Western blots and immunohistochemistry, indicate a greater expression of the inducible enzyme in bile duct ligated and L-arginine-treated animals and a lower expression in the L-NAME and control groups. Constitutive nitric oxide synthase expression, obtained by Western blots, was very similar in all groups, except for the L-arginine-treated rats in which it was lower. These results suggest that nitric oxide production may be a key factor in the development of fibrosis in bile duct ligated rats. They also support the hypothesis of a dual role for nitric oxide; one beneficial, mediated by its circulatory effects, and the second negative, through its local toxic effects.

Animals↗