Analysis of Individual and Combined Effects of Ochratoxin A and Zearalenone on HepG2 and KK-1 Cells with Mathematical Models

Abstract

Ochratoxin A (OTA) and Zearalenone (ZEA) are widespread mycotoxins that contaminate foodstuffs simultaneously, but sufficient data regarding their mixed toxicities are lacking. This study aims to analyze the style of combined effects of OTA and ZEA on cells of their target organs. For this purpose, cytotoxicity was determined in HepG2 and KK-1 cells treated with single and combined forms of OTA and ZEA. Furthermore, we have analyzed the data using two mathematical models based on the concepts of concentration addition (CA) and independent addition (IA). By analyzing data with nonlinear regression, toxins applied singly showed classic sigmoid dose-response curves in HepG2 cells whereas in KK-1 cells hormetic responses were observed. Exposure to equieffective mixtures of OTA and ZEA showed additive effects, irrespective of different nonlinear regression models used. Our results demonstrate that IA is an appropriate concept to account for mixture effects of OTA and ZEA. The results in ROS generation indicate a departure from additivity to antagonism or synergism at different concentrations, probably due to potential interaction during ROS production. This study shows that a risk assessment of mycotoxins should account for mixture effects, and prediction models are valuable tools for mixture assessment.

Zearalenone Induces Endoplasmic Reticulum Stress and Modulates the Expression of Phase I/II Enzymes in Human Liver Cells

“…These data suggest that cellular oxidative stress plays a critical role in the observed apoptosis. In previous studies, similar results were observed in HepG2 and porcine IPEC-J2 cells as ZEN generated ROS, reduced antioxidant enzyme activities, and induced cell death in vitro [24][25][26].…”

Toxicity of Quaternary Mixtures of Phenolic Compounds and Formulated Glyphosate to Microbial Community of River Water

“…The MDR and TI values indicated slight synergistic and antagonistic interactions among the components of the chemical mixtures. Nevertheless, the values are within 0.5 -2.0 range, thus the mixtures are said to be additive (Petersen & Tollefsen, 2011;Li et al, 2014).…”

Assessing the Effect of Mycotoxin Combinations: Which Mathematical Model Is (the Most) Appropriate?

“…This does not seem to be correct according to the dose-response curves for OTA (E (1.60 µM of OTA) ≈ 30%) and ZEN (E (23.68 µM of ZEN) ≈ 50%) presented in aforementioned article [44], which raises the question: can the observed synergies be trusted at all? Even though this model is mathematically valid, due to the excessive number of assumptions that need to be fulfilled, this model probably remains inapplicable for assessing combinations of mycotoxins [43].…”

“…Finding two mycotoxins in a combination that fulfils all of these assumptions seems somewhat impossible. For example, apart from the Bliss independence criterion, Li et al [44] also used this method (as a concentration addition model) to assess the nature of interaction between OTA and ZEN. Since their dose-effect curves did not meet all of the assumptions, it is easy to see that Equation 4, on which Loewe's additivity law is based, does not hold true when we assign the values EC 10 (OTA) = 0.8 µM and EC 10 (ZEN) = 11.84 µM [44], and try to apply the main principles of dose equivalence and sham combination of this model (Equations 7and 8…”