“Responses of zebrafish (Danio rerio) hepatocytes co-exposed to benzo[a]pyrene and to the carbon nanomaterial fullerene (C60)”

LONNÉ, M.N.; RIBAS FERREIRA, J.L.; SOARES CHAVES, I.; DE LA TORRE, F.R.; MONSERRAT, J.M

Santa Fe, Argentina.

Congreso; III Congreso Argentino de la Sociedad de Toxicología y Química Ambiental (SETAC).; 2010

&amp;amp;amp;amp;lt;!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611985 1107304683 0 0 159 0;} @font-face {font-family:Tahoma; panose-1:2 11 6 4 3 5 4 4 2 4; mso-font-charset:0; mso-generic-font-family:swiss; mso-font-pitch:variable; mso-font-signature:-520082689 -1073717157 41 0 66047 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES; mso-fareast-language:ES;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt;} @page WordSection1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.WordSection1 {page:WordSection1;} --&amp;amp;amp;amp;gt; &amp;amp;amp;lt;!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611985 1107304683 0 0 159 0;} @font-face {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4; mso-font-charset:0; mso-generic-font-family:swiss; mso-font-pitch:variable; mso-font-signature:-1610611985 1073750139 0 0 159 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin-top:0cm; margin-right:0cm; margin-bottom:10.0pt; margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-fareast-font-family:Calibri; mso-bidi-font-family:"Times New Roman"; mso-ansi-language:PT-BR; mso-fareast-language:EN-US;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt; mso-ascii-font-family:Calibri; mso-fareast-font-family:Calibri; mso-hansi-font-family:Calibri;} @page WordSection1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.WordSection1 {page:WordSection1;} --&amp;amp;amp;gt; In this study the toxic responses in zebrafish hepatocytes co-exposed to the polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) and the carbon nanomaterial fullerene (C60) were analyzed. Hepatocytes were kept at 28 °C, in RPMI culture medium with 10% BSA. Mitochondrial functionality (MF), registered by MTT reduction, was used as a cell viability estimate. Concentrations of 0.01, 0.1 and 1.0 mg BaP/L did not alter the viability when compared to  control group and the opposite was observed for the concentrations of 10.0 and 100.0 mg BaP/L (p<0.05). Then, the effect of co-exposure to BaP (0.01-1.0 mg BaP/L) with 1 mg C60/L -a concentration that did not alter cell viability- was evaluated. After 4 h of incubation, several parameters were evaluated:  MF and intracellular concentration of reactive oxygen species (ROS); glutathione-S-transferase (GST) activity and intracellular accumulation of BaP and its metabolites. Regarding ROS, results showed that co-exposure of hepatocytes to 1.0 mg BaP/L and 1 mg C60/L caused a significant decrease in their concentration in relation to cells only exposed to 1.0 mg/L BaP. GST activity increased in a dose-dependent manner (p<0.05) without C60 for 0.1 and 1 mg/mL BaP concentrations and in presence of C60, a significant reduction was observed for all concentrations tested. In addition, the intracellular accumulation of BaP and its metabolites was significantly higher both in presence and absence of C60 for the 1 mg/L of BaP concentration. In relation to ROS, the result cannot be interpreted as an antioxidant effect because at the same time a lower MTT reduction capacity was observed for all three concentrations of BaP when co-exposed with C60. Taking into account that mitochondria are the main source of ROS production, the decrease in their concentration and the lower MF in hepatocytes exposed to BaP and C60 suggest that mitochondrial functionality was altered. The GST activity was higher for increasing values of BaP concentration, as expected, but the presence of C60 caused a significant loss in the detoxifying capacity of the cells.