María Luisa Mendoza-Magaña

DNA damage in mouse lymphocytes exposed to curcumin and copper.

Dietary polyphenolics, such as curcumin, have shown antioxidant and anti-inflammatory effects. Some antioxidants cause DNA strand breaks in excess of transition metal ions, such as copper. The aim of this study was to evaluate thein vitro effect of curcumin in the presence of increasing concentrations of copper to induce DNA damage in murine leukocytes by the comet assay. Balb-C mouse lymphocytes were exposed to 50 μM curcumin and various concentrations of copper (10 μM, 100 μM and 200 μM). Cellular DNA damage was detected by means of the alkaline comet assay. Our results show that 50 μM curcumin in the presence of 100–200 μM copper induced DNA damage in murine lymphocytes. Curcumin did not inhibit the oxidative DNA damage caused by 50 μM H2O2 in mouse lymphocytes. Moreover, 50 μM curcumin alone was capable of inducing DNA strand breaks under the tested conditions. The increased DNA damage by 50 μM curcumin was observed in the presence of various concentrations of copper, as detected by the alkaline comet assay.

Protectivein vivo effect of curcumin on copper genotoxicity evaluated by comet and micronucleus assays

Curcumin is a phytochemical with antiinflammatory, antioxidant and anticarcinogenic activities. Apparently, curcumin is not genotoxicin vivo, butin vitro copper and curcumin interactions induce genetic damage. The aim of this study was to test ifin vivo copper excess induces DNA damage measured by comet and micronucleus assays in the presence of curcumin. We tested 0.2% curcumin in Balb-C mice at normal (13 ppm) and high (65, 130 and 390 ppm) copper ion concentrations. The comet and micronucleus assays were performed 48 hr after chemical application. Comet tail length in animals treated with 0.2% curcumin was not significantly different from the control. Animals exposed to copper cations (up to 390 ppm) exhibited higher oxidative DNA damage. Curcumin reduced the DNA damage induced by 390 ppm copper. We observed statistically significant increase in damage in individuals exposed to 390 ppm copper versus the control or curcumin groups, which was lowered by the presence of curcumin. Qualitative data on comets evidenced that cells from individuals exposed to 390 ppm copper had longer tails (categories 3 and 4) than in 390 ppm copper + curcumin. A statistically significant increase in frequency of micronucleated erythrocytes (MNE/10000TE) was observed only in 390 ppm copper versus the control and curcumin alone. Also cytotoxicity measured as the frequency of polychromatic erythrocytes (PE/1000TE) was attributable to 390 ppm copper. The lowest cytotoxic effect observed was attributed to curcumin.In vivo exposure to 0.2% curcumin for 48 hr did not cause genomic damage, while 390 ppm copper was genotoxic, but DNA damage induced by 390 ppm copper was diminished by curcumin. Curcumin seems to exert a genoprotective effect against DNA damage induced by high concentrations of copper cations. The comet and micronucleus assays prove to be suitable tools to detect DNA damage by copper in the presence of curcumin.

Curcumin protects against the oxidative damage induced by the pesticide parathion in the hippocampus of the rat brain

Abstract One of the main concerns regarding organophosphate pesticides (OP) is their possible toxic effects. Doses that do not produce acute toxicity are capable of altering the structure and biochemistry of different tissues and organs by production of reactive oxygen species (ROS). Curcumin (CUR) is the main substance in Curcuma longa (Zingiberacea) rhizome that has strong antioxidant activity. However, the neuroprotective properties of curcumin against oxidative stress induced by prolonged exposure to parathion (PAR) is not clear. Objective The present work evaluated the protective effect of curcumin against the oxidative damage induced in the rat hippocampus by the OP PAR. Methods Forty female Wistar rats were distributed in four groups as follows: exposed to PAR by inhalation (PAR group); pre-treated with CUR and then exposed to PAR by inhalation, (CUR + PAR group); exposed to environmental air and treated with CUR in the food (CUR group); and exposed to environmental air (the control group). At the end of the handling process, the concentration of erythrocyte cholinesterase was monitored, as indicator of PAR intoxication and lipoperoxidation, immunohistochemistry for astrocytes, and activated microglia and apoptosis was determined in the hippocampus. Results In the present study, we show that the administration of CUR (200 mg/kg body weight) significantly diminished the oxidative damage in the hippocampus of rats exposed to the OP PAR. Discussion These data suggest that CUR may be an alternative to prevent neurodegenerative damage after pesticide exposure.

Changes in the content of GFAP in the rat brain during pregnancy and the beginning of lactation

Several changes in brain function, including learning and memory, have been reported during pregnancy but the molecular mechanisms involved in these changes are unknown. Due to the fundamental role of glial cells in brain activity, we analyzed the content of glial fibrillary acidic protein (GFAP) in the hippocampus, frontal cortex, preoptic area, hypothalamus and cerebellum of the rat on days 2, 14, 18, and 21 of pregnancy and on day 2 of lactation by Western blot. A differential expression pattern of GFAP was found in the brain during pregnancy and the beginning of lactation. GFAP content was increased in the hippocampus throughout pregnancy, whereas a decrease was observed in cerebellum. GFAP content was increased in the frontal cortex and hypothalamus on days 14 and 18, respectively, with a decrease in the following days of pregnancy in both regions. In preoptic area a decrease in GFAP content was observed on day 14 with an increase on days 18 and 21. In the frontal cortex and cerebellum, GFAP content was increased on day 2 of lactation, while it was maintained as on day 21 of pregnancy in the other regions. Our data suggest a differential expression pattern of GFAP in the rat brain during pregnancy and the beginning of lactation that should be associated with changes in brain function during these reproductive stages.

Curcumin alters the cytoskeleton and microtubule organization on trophozoites of Giardia lamblia

Giardia lamblia is a worldwide protozoan responsible for a significant number of intestinal infections. There are several drugs for the treatment of giardiasis, but they often cause side effects. Curcumin, a component of turmeric, has antigiardial activity; however, the molecular target and mechanism of antiproliferative activity are not clear. The effects of curcumin on cellular microtubules have been widely investigated. Since tubulin is the most abundant protein in the cytoskeleton of Giardia, to elucidate whether curcumin has activity against the microtubules of this parasite, we treated trophozoites with curcumin and the cells were analyzed by scanning electron microscopy and confocal microscopy. Curcumin inhibited Giardia proliferation and adhesion in a time-concentration-dependent mode. The higher inhibitory concentrations of curcumin (3 and 15μM) disrupted the cytoskeletal structures of trophozoites; the damage was evident on the ventral disk, flagella and in the caudal region, also the membrane was affected. The immunofluorescence images showed altered distribution of tubulin staining on ventral disk and flagella. Additionally, we found that curcumin caused a clear reduction of tubulin expression. By docking analysis and molecular dynamics we showed that curcumin has a high probability to bind at the interface of the tubulin dimer close to the vinblastine binding site. All the data presented indicate that curcumin may inhibit Giardia proliferation by perturbing microtubules.

Electrophysiological and morphological alterations in peripheral nerves by the pig paramyxovirus of blue eye disease in neonatal pigs.

The pig paramyxovirus of blue eye disease (PPBED) produces central nervous system (CNS) damage leading to death in piglets. However, when PPBED was injected into the muscle and came into contact with hind limb peripheral nerves and was transported to the CNS, it did not cause death and could be a mechanism by which to induce protection. This study analyses whether PPBED causes electrophysiological and morphological alterations in infected hind limb peripheral nerves. It also studies, whether PPBED induces the onset of haemagglutination inhibitory antibodies (HIA) when it is transported to the spinal cord after medial gastrocnemius (MG) intramuscular injection. PPBED was detected by an immunohistochemical method and nerve morphology was studied using electron microscopy. The physiological status of the nerve was evaluated with electrophysiological techniques. The electrical threshold of the infected MG nerve increased four- or five fold compared to that in the ipsilateral lateral gastrocnemius or in the MG nerve on the control side. The infected nerve fibres underwent myelin sheet disarrangement and their internal fibre diameter decreased. PPBED induced the onset of HIA.