Evaluation of the clastogenicity and anticlastogenicity of the carotenoid bixin in human lymphocyte cultures

Carotenoids are regarded as effective antioxidants, antimutagenic and anticarcinogenic agents. Annatto, a red-yellow extract obtained from seeds of Bixa orellana L. is a mixture of several carotenoids and one of them bixin (BXN), is known as its major coloring compound. Studies on BXN clastogenicity and anticlastogenicity in cultured human lymphocytes have not been reported so far. Therefore, the present study was undertaken to investigate the ability of BXN to induce chromosomal aberrations in human lymphocytes in vitro and to examine the possible anticlastogenic effect of this carotenoid in chromosomal damage induced by the clastogen cisplatin (cDDP). Human blood samples were obtained from six healthy, non-smoking volunteers; two females and four males aged 18-35 years. The concentrations of BXN (1.0; 2.5; 5.0 or 10 microg/mL) tested in combination with cDDP were established on the basis of mitotic index (MI) measurements. The data showed that BXN was not cytotoxic or clastogenic, when compared to untreated control. A marked decrease in the MI values compared to the untreated control and an increased percentage of aberrant metaphases was seen in all cultures treated with cDDP. The carotenoid efficiency in reducing the inhibitory effect of cDDP on lymphocyte MI is concentration-dependent. Cultures simultaneously treated with BXN and cDDP showed a statistically significant reduction in total chromosomal aberrations and aberrant metaphases. In our experiments, BXN may have acted as an antioxidant by intercepting free radicals generated by cDDP. The data obtained in the present study suggest that dietary carotenoids may act as protective agents against clastogenic effects of antitumor agents. However, extensive studies are necessary to elucidate the mechanism of action of BXN before its therapeutic use.     

Partial characterization of digestive proteases in Totoaba (Totoaba macdonaldi)

ABSTRACT

The objective of this study was to characterize the digestive proteases of totoaba (Totoaba macdonaldi). Fish were sacrificed to obtain the multienzymatic extracts from the stomach and intestine, and determine the stability and optimum pH and temperature values. Residual activity and number of isoforms were determined with some inhibitors. Optimal pH of stomach proteases was 2, with stability above 100% at that same pH. Optimum pH of intestinal proteases was between 9 and 11, with stability above 100% between 8-12. Optimum temperature for stomach proteases was 35°C and remained highly stable, while optimum temperature for intestinal proteases was 45°C, with high stability between 35-55°C. Pepstatin A totally inhibited acid protease activity and revealed a single band. SDS-PAGE zymogram revealed 8 bands in the intestine, where phenanthroline inhibited 80% of the total activity. The digestive capacity of T. macdonaldi is characteristic of a strict carnivore, similar to other marine fish species.     

Evaluation of the genotoxic and antigenotoxic effects after acute and subacute treatments with açai pulp (Euterpe oleracea Mart.) on mice using the erythrocytes micronucleus test and the comet assay

Açai, the fruit of a palm native to the Amazonian basin, is widely distributed in northern South America, where it has considerable economic importance. Whereas individual polyphenolics compounds in açai have been extensively evaluated, studies of the intact fruit and its biological properties are lacking. Therefore, the present study was undertaken to investigate the in vivo genotoxicity of açai and its possible antigenotoxicity on doxorubicin (DXR)-induced DNA damage. The açai pulp doses selected were 3.33, 10.0 and 16.67 g/kg b.w. administered by gavage alone or prior to DXR (16 mg/kg b.w.) administered by intraperitoneal injection. Swiss albino mice were distributed in eight groups for acute treatment with açai pulp (24 h) and eight groups for subacute treatment (daily for 14 consecutive days) before euthanasia. The negative control groups were treated in a similar way. The results of chemical analysis suggested the presence of carotenoids, anthocyanins, phenolic, and flavonoids in açai pulp. The endpoints analyzed were micronucleus induction in bone marrow and peripheral blood cells polychromatic erythrocytes, and DNA damage in peripheral blood, liver and kidney cells assessed using the alkaline (pH >13) comet assay. There were no statistically significant differences (p > 0.05) between the negative control and the groups treated with the three doses of açai pulp alone in all endpoints analyzed, demonstrating the absence of genotoxic effects. The protective effects of açai pulp were observed in both acute and subacute treatments, when administered prior to DXR. In general, subacute treatment provided greater efficiency in protecting against DXR-induced DNA damage in liver and kidney cells. These protective effects can be explained as the result of the phytochemicals present in açai pulp. These results will be applied to the developmental of food with functional characteristics, as well as to explore the characteristics of açai as a health promoter.     

Evaluation of the genotoxicity of Crotalus durissus terrificus snake venom and its isolated toxins on human lymphocytes

In the present study, experiments were carried out to evaluate the mutagenic potential and genotoxic effects of Crotalus durissus terrificus snake venom and its isolated toxins on human lymphocytes, using the micronucleus and comet assays. Significant damage to DNA was observed for crotoxin and crotapotin (CA). Basic phospholipase A(2) (CB) and crotamine did not present any mutagenic potential when evaluated by the micronucleus test. C. d. terrificus crude venom was able to induce the formation of micronuclei, similarly to the mutagenic drug used as a positive control. In the comet assay, all the toxins tested (crotamine, crotoxin, CB and CA) and C. d. terrificus venom presented genotoxic activity. Studies on the cytogenetic toxicology of animal venoms and their isolated proteins are still very scarce in the literature, which emphasizes the importance of the present work for the identification and characterization of potential therapeutic agents, as well as for the better understanding of the mechanisms of action of toxins on the human body.     

Gold-Coated Superparamagnetic Iron Oxide Nanoparticles Attenuate Collagen-Induced Arthritis after Magnetic Targeting

Biological Trace Element Research - Fluoride can induce neurotoxicity, but the mechanism is not clear. In this study, we explored the role of autophagy in F−-induced neurotoxicity of Wistar...     

Acetylsalicylic acid exhibits anticlastogenic effects on cultured human lymphocytes exposed to doxorubicin

Acetylsalicylic acid (ASA) is a non-steroidal anti-inflammatory drug (NSAID) with many pharmacological properties, such as anti-inflammatory, antipyretic and analgesic. Many studies have suggested the possible efficiency of ASA and other NSAIDs in preventing cancer. ASA could also have antimutagenic and antioxidant properties. The aim of this study was to investigate the possible clastogenic and anticlastogenic effects of different concentrations of ASA on doxorubicin-induced chromosomal aberrations in human lymphocytes. Human blood samples were obtained from six healthy, non-smoking volunteers; and the chromosomal aberration assay was carried out using conventional techniques. The parameters analyzed were mitotic index, total number of chromosomal aberrations and percentage of aberrant metaphases. The concentrations of ASA (25, 50 or 100 microg/mL) tested in combination with DXR (0.2 microg/mL) were established on the basis of the results of the mitotic index. The treatment with ASA alone was neither cytotoxic nor clastogenic (p>0.01). In lymphocyte cultures treated with different combinations of ASA and DXR, a significant decrease in the total number of chromosome aberrations was observed compared with DXR alone (p<0.01). This protective effect of ASA on DXR-induced chromosomal damage was obtained for all combinations, and it was most evident when ASA was at 25.0 microg/mL. In our experiments, ASA may have acted as an antioxidant and inhibited the chromosomal damage induced by the free radicals generated by DXR. The identification of compounds that could counteract the free radicals produced by doxorubicin could be of possible benefits against the potential harmful effects of anthracyclines. The results of this study show that there is a relevant need for more investigations in order to elucidate the mechanisms underlying the anticlastogenic effect of ASA.     

The effects of oral glutamine on cisplatin-induced genotoxicity in Wistar rat bone marrow cells

Several studies have suggested that dietary supplementation with antioxidants can influence the response to chemotherapy as well as the development of adverse side effects that result from treatment with antineoplastic agents. The emphasis of the present study was to investigate whether the administration of a single dose of oral glutamine had any protective effect against cisplatin-induced clastogenicity. Cisplatin was administered to Wistar rats either alone or after treatment with glutamine. The rats were treated with glutamine (300 mg/kg b.w.) by gavage 24h before the administration of cisplatin (5mg/kg b.w., i.p.) and then sacrificed 24h after treatment with cisplatin. Glutamine significantly reduced (by about 48%) the clastogenicity of cisplatin in rat bone marrow cells. The antioxidant action of glutamine presumably modulates the clastogenic action of cisplatin.     

Expression and activity of trypsin and pepsin during larval development of the spotted rose snapper Lutjanus guttatus

The present study aimed to describe and understand the development of the digestive system in spotted rose snapper (Lutjanus guttatus) larvae from hatching to 40 days post-hatch (dph). The mouth opened between 2 and 3 dph, at that moment the digestive tract was barely differentiated into the anterior and posterior intestine, although the liver and pancreas were already present. Gastric glands were observed until 20 dph, followed by the differentiation of the stomach between 20 and 25 dph. Trypsinogen expression and trypsin activity were detected at hatching, increasing concomitantly to larval development and the change in the type of food. Maximum levels of trypsinogen expression were observed at 25 dph, when animals were fed with Artemia nauplii, and maximum trypsin activity was detected at 35 dph, when larvae were fed with an artificial diet. On the other hand, pepsinogen gene expression was detected at 18 dph, two days before pepsin enzymatic activity and appearance of gastric glands. Maximum pepsin activity was also observed at 35 dph. These results suggest that in this species weaning could be initiated at an earlier age than is currently practiced (between 28 and 30 dph), since larvae of spotted rose snapper develop a functional stomach between days 20 and 25 post-hatch.     

Cytogenetic biomonitoring of inhabitants of a large uranium mineralization area: the municipalities of Monte Alegre, Prainha, and Alenquer, in the State of Pará, Brazil

Uranium is a natural radioactive metallic element; its effect on the organism is cumulative, and chronic exposure to this element can induce carcinogenesis. Three cities of the Amazon region—Monte Alegre, Prainha, and Alenquer—in North Brazil, are located in one of the largest uranium mineralization areas of the world. Radon is a radioactive gas, part of uranium decay series and readily diffuses through rock. In Monte Alegre, most of the houses are built of rocks removed from the Earth’s crust in the forest, where the uranium reserves lie. The objective of the present work is to determine the presence or absence of genotoxicity and risk of carcinogenesis induced by natural exposure to uranium and radon in the populations of these three cities. The frequency of micronuclei (MN) and chromosomal aberrations (CA) showed no statistically significant differences between the control population and the three study populations (P > 0.05). MN was also analyzed using the fluorescence in situ hybridization (FISH) technique, with a centromere-specific probe. No clastogenic and/or aneugenic effects were found in the populations. Using FISH analysis, other carcinogenesis biomarkers were analyzed, but neither the presence of the IGH/BCL2 translocation nor an amplification of the MYC gene and 22q21 region was detected. Clastogenicity and DNA damage were also not found in the populations analyzed using the alkaline comet assay. The mitotic index showed no cytotoxicity in the analyzed individuals’ lymphocytes. Once we do not have data concerning radiation doses from other sources, such as cosmic rays, potassium, thorium, or anthropogenic sources, it is hard to determine if uranium emissions in this geographic region where our study population lives are too low to cause significant DNA damage. Regardless, genetic analyses suggest that the radiation in our study area is not high enough to induce DNA alterations or to interfere with mitotic apparatus formation. It is also possible that damages caused by radiation doses undergo cellular repair.