Efeito da ocratoxina A em suco de uva tinto sobre sobrevivência e geração de EROs em Caenoaerbiditis elegans / Effects of ochratoxin A in red grape juice on survival rate and ROs generation in Caenoaerbiditis elegans

O consumo do suco de uva vem crescendo ao longo dos anos em função das suas propriedades funcionais. No entanto, este produto não está livre de contaminantes como a ocratoxina A (OTA). O presente trabalho teve por objetivo avaliar o efeito da presença de OTA em suco de uva Concord sobre geração de espécies reativas de oxigênio (EROs) e taxa de sobrevivência em Caenoarbiditis elegans. Os vermes foram expostos por 30 minutos ao suco na presença de OTA (0, 1, 2 e 4 µg∙L-1). O suco em presença de OTA não afetou a sobrevivência do C. Elegans. A adição de suco livre de OTA reduziu a sobrevivência dos nematoides, embora não tenha influenciado a geração de EROs. Contudo o suco com a concentração mais elevada de OTA reduziu a geração de EROs. Assim, são necessários maiores estudos para entender os mecanismos de toxicidade da OTA neste modelo vivo.

effect of ochratoxin on antimicrobial polypeptide expression in channel catfish [Ictalurus punctatus]

Mycotoxins contamination of agricultural commodities poses a serious risk to animal health, including aquaculture species. While chronic effects of mycotoxins, including immunosupression, are much more important than acute toxicities, they are much less evident. Ochratoxin A [OA] is the most immunotoxic ochratoxin, yet little is known about its effect on immune function in fish. Antimicrobial polypeptides [AMPPs] are one of the most potent, innate, host defense factors, yet very little is known about what types of chronic stressors affect their expression. Among the most prevalent and potent AMPPs in fish are histone-like proteins [HLP]. In this study, fish were fed 2, 4, or 8 ppm OA. Skin antibacterial activity was measured on Days 0, 28 and 56. Feeding 2, 4 or 8 ppm OA resulted in no changes in AMPP expression in any treatment group. Our data suggests that the immunosuppression of OA is probably due to impaired cell-mediated immune mechanisms other than a direct effect on antimicrobial polypeptide expression

DNA damage by ochratoxin A in rat kidney assessed by the alkaline comet assay

There are few studies of ochratoxin A (OTA) genotoxicity in experimental animals and the results obtained with cell cultures are inconsistent, although the carcinogenic potential of OTA for the kidney of experimental animals has been well established. We studied the genotoxic potential of OTA in the kidney of adult female Wistar rats (5 in each group) treated intraperitoneally with OTA (0.5 mg kg body weight-1 day-1 for 7, 14, and 21 days) measuring DNA mobility on agarose gel stained with ethidium-bromide using standard alkaline single-cell gel electrophoresis (comet assay). Negative control animals were treated with solvent (Tris buffer, 1.0 mg/kg) and positive control animals were treated with methyl methanesulfonate (40 mg/kg) according to the same schedule. OTA concentrations in plasma and kidney homogenates in 7-, 14-, and 21-day treated animals were 4.86 ± 0.53, 7.52 ± 3.32, 7.85 ± 2.24 æg/mL, and 0.87 ± 0.09, 0.99 ± 0.06, 1.09 ± 0.15 æg/g, respectively. In all OTA-treated groups, the tail length, tail intensity, and tail moment in kidney tissue were significantly higher than in controls (P < 0.05). The tail length and tail moment were higher after 14 days than after 7 days of treatment (P < 0.05), and still higher after 21 days (P < 0.05). The highest tail intensity was observed in animals treated for 21 days, and it differed significantly from animals treated for 7 and 14 days (P < 0.05). OTA concentrations in plasma and kidney tissue increased steadily and OTA concentration in kidney tissue strongly correlated with tail intensity and tail moment values. These results confirm the genotoxic potential of OTA, and show that the severity of DNA lesions in kidney correlates with OTA concentration.

Ochratoxin induced hemolysis in rabbits.

A saline suspension of RBC when incubated with an increasing concentration (1 to 10 micrograms/ml) of crude ochratoxin at 37 degrees C for 16 hr showed a marked alteration in morphological characters followed by hemolysis. The effect was more pronounced with higher concentration of toxin. The result suggests extreme cytotoxic effect of ochratoxin on RBC leading to its lysis.