Analysis of combined effects of nonylphenol and Monobutyl phthalate on rat Sertoli cells applying two mathematical models

Nonylphenol (NP) and Monobutyl phthalate (MBP) are two environmental endocrine disruptors (EEDs) which are widespread occurrence in our life. In present study, our purpose is to analyze style of combined effects of NP and MBP on rat testicular Sertoli cell in vitro using two mathematical models based on the Loewe additivity (LA) theory and the Bliss independence (BI) theory. Sertoli cells were administrated by NP (range 0.01–50 μM) and MBP (range 10–20000 μM) in single and combined forms. Cell viability and lactate dehydrogenase (LDH) leakage rate were employed as endpoints. Using the two models, a significant antagonist effect was observed both in the viability assay and in the LDH assay (at concentrations provoked LDH leakage rate >20%), but at the lower concentrations which induced LDH leakage rate <20%, the combined effect was synergism. Considering the environmental contaminants are frequently encountered simultaneously, the result indicated that the combined effect of chemical mixture needed to be set a high value in EEDs risk assessment.