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Journal Article

Effects of Aflatoxin B1 on Chicken Chondrocytes in Culture

Faouzi Kichou and Mary M. Walser
Avian Diseases
Vol. 38, No. 1 (Jan. - Mar., 1994), pp. 11-15
DOI: 10.2307/1591830
Stable URL: http://www.jstor.org/stable/1591830
Page Count: 5
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Effects of Aflatoxin  B1 on Chicken Chondrocytes in Culture
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Abstract

In vitro effects of aflatoxin B1 on DNA and proteoglycan synthesis were assessed by measuring tritiated thymidine and radiosulfate incorporation by chicken chondrocyte cultures. Chondrocytes were harvested from the growth-plate cartilage of a 35-day-old chicken, cultured in triplicate, and treated with 0, 1, 5, 10, or 25 μg aflatoxin B1/ ml of culture medium. The cultures were then spiked separately with [3 H]thymidine or [35 S]sulfate. After the cells, matrix, and medium were harvested, radioactivity was measured by a scintillation counter. Aflatoxin B1 resulted in a dose-dependent inhibition of DNA synthesis, as measured by tritiated thymidine incorporation by chicken chondrocytes: 54.6%, 30.9%, 25.9%, and 5.9% of control in cultures treated with 1, 5, 10, and 25 μg aflatoxin B1/ ml of culture medium, respectively (P < 0.05). Sulfated proteoglycan synthesis, as measured by radiosulfate incorporation in chondrocyte cultures, was decreased in the media and intercellular matrix by all aflatoxin B1 levels. Compared with controls, 21% less (P < 0.05) radiosulfate was incorporated into non-matrix macromolecules of the medium fraction from chondrocytes exposed to 1 μg aflatoxin B1/ ml. However, 5 μg aflatoxin B1/ ml was necessary to produce a significant decrease in radiosulfate incorporation in proteoglycans of intercellular matrix (34% less than controls). The ratios of the means of radiosulfate incorporation into intercellular macromolecules to the means of tritiated thymidine incorporation indicated that aflatoxin B1 inhibited DNA synthesis more than proteoglycan synthesis. /// Se evaluaron los efectos in vitro de la aflatoxina B1, sobre el ADN y la síntesis de proteoglican, mediante la incorporación de timidina tritiada y radiosulfato, en cultivos de condrocitos de pollo. Los condrocitos fueron cosechados del cartílago de la placa de crecimiento de pollos de 35 días de edad cultivados en triplicado, y tratados con 0, 1, 5, 10 o 25 μg de aflatoxina B1 por ml de medio de cultivo. Los cultivos fueron tratados separadamente con [3 H]timidina ó con [35 S]sulfato. Después de que se cosecharon las células y el medio, la radioactividad fue medida. El tratamiento con aflatoxina B1 resultó en una inhibición de la síntesis del ADN relacionada con la dosis, medida por la incorporación de timidina tritiada en los condrocitos de pollo: 54.6%, 30.9%, 25.9% y 5.9% de control en los cultivos tratados con 1, 5, 10 y 25 μg de aflatoxina por ml de medio de cultivo respectivamente (P < 0.05). La síntesis del proteoglican sulfonado, medido por la incorporación del radiosulfato en los cultivos de condrocitos, disminuyó en el medio y en la matriz intercelular para todos los niveles de tratamiento con aflatoxina B1. Se incorporó el 21% menos de radiosulfato (P < 0.05) en las macromoléculas sin matriz de la fracción del medio de los condrocitos expuestos a 1 μg de aflatoxina B1 por ml. Sin embargo, fueron necesarios 5 μg de aflatoxina B1 por ml, para producir una disminución significante en la incorporación de radiosulfato en el proteoglican de la matriz intercelular (34% menos que los controles). Las proporciones de los promedios de incorporación de radiosulfato en las macromoléculas intercelulares frente a los promoedios de incorporación de timidina tritiada, indicaron que la aflatoxina B1 inhibió la síntesis del ADN en mayor proporción que la síntesis del proteoglican.

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