Liliana Saldívar | PubMed Health

PubMed2005

Time course study of oxidative and nitrosative stress and antioxidant enzymes in K2Cr2O7-induced nephrotoxicity.

BACKGROUND: Potassium dichromate (K2Cr2O7)-induced nephrotoxicity is associated with oxidative and nitrosative stress. In this study we investigated the relation between the time course of the oxidative and nitrosative stress with kidney damage and alterations in the following antioxidant enzymes: Cu, Zn superoxide dismutase (Cu, Zn-SOD), Mn-SOD, glutathione peroxidase (GPx), glutathione reductase (GR), and catalase (CAT). METHODS: Nephrotoxicity was induced in rats by a single injection of K2Cr2O7. Groups of animals were sacrificed on days 1,2,3,4,6,8,10, and 12. Nephrotoxicity was evaluated by histological studies and by measuring creatinine clearance, serum creatinine, blood urea nitrogen (BUN), and urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) and total protein. Oxidative and nitrosative stress were measured by immunohistochemical localization of protein carbonyls and 3-nitrotyrosine, respectively. Cu, Zn-SOD, Mn-SOD, and CAT were studied by immunohistochemical localization. The activity of total SOD, CAT, GPx, and GR was also measured as well as serum and kidney content of chromium and urinary excretion of NO2 -/NO3-. Data were compared by two-way analysis of variance followed by a post hoc test. RESULTS: Serum and kidney chromium content increased reaching the highest value on day 1. Nephrotoxicity was made evident by the decrease in creatinine clearance (days 1-4) and by the increase in serum creatinine (days 1-4), BUN (days 1-6), urinary excretion of NAG (days 1-4), and total protein (day 1-6) and by the structural damage to the proximal tubules (days 1-6). Oxidative and nitrosative stress were clearly evident on days 1-8. Urinary excretion of NO2-/NO3- decreased on days 2-6. Mn-SOD and Cu, Zn-SOD, estimated by immunohistochemistry, and total SOD activity remained unchanged. Activity of GPx decreased on days 3-12 and those of GR and CAT on days 2-10. Similar findings were observed by immunohistochemistry of CAT. CONCLUSION: These data show the association between oxidative and nitrosative stress with functional and structural renal damage induced by K2Cr2O7. Renal antioxidant enzymes were regulated differentially and were not closely associated with oxidative or nitrosative stress or with kidney damage. In addition, the decrease in the urinary excretion of NO2-/NO3- was associated with the renal nitrosative stress suggesting that nitric oxide was derived to the formation of reactive nitrogen species involved in protein nitration.

Acetylglucosaminidase↗

PubMed2005

Zinc concentrations during mice gestation.

Severe maternal zinc deficiency has a devastating effect on pregnancy outcome. Studies of humans and experimental animals show that maternal zinc deficiency can cause infertility, prolonged labor, intrauterine growth retardation, teratogenesis, severe immunological deficiencies, or fetal death. The additional need for zinc during pregnancy can be met by an increase in zinc intake. An increase in zinc supplements, when excessive, can cause a decrease in copper. Therefore, it is important to determine the zinc and copper concentrations in embryonic tissue in experimental models and their relationship with embryo number and viability. BALB/c mice were divided into groups according to zinc oral supplementation and gestational age. Phagocytosis was assessed in peritoneal macrophages from dams. The zinc and copper concentrations were obtained by inductively coupled plasma-optical emission spectrometry. Zn and Cu data concentrations in all the analyzed samples were above the detection limits. No spectral interferences were found in both elements. Zinc concentrations show a tendency to increase in embryos (14 gestational days and 21 gestational days) supplemented with zinc. Copper concentrations showed a noticeable tendency to diminish (36% and 27%, respectively) in the same period. In contrast, in placenta Zn values were increased by 30% and Cu values were decreased by 26%. We suggest a pivotal role of the placenta metabolism with its homeostatic mechanisms, in these findings. An important increment appeared in the +Zn embryo number (40%) relative to control (-Zn) embryos at 21 d gestational age. Embryo mortality was at 6% in +Zn embryos and at 20% in -Zn embryos. We consider these findings, both in the number and in the viability of +Zn embryos, outstanding.

Animals↗