Mycotoxin zearalenone exposure impairs genomic stability of swine follicular granulosa cells in vitro

Abstract

Zearalenone (ZEA) a metabolite of Fusarium fungi is commonly found on moldy grains. Because it can competitively combine to estrogen receptor to disrupt estrogenic signaling it has been reported to have serious adverse effects on animal reproduction systems. In order to explore the genotoxic effects of ZEA exposure on ovarian somatic cells porcine granulosa cells were exposed to 10 μM and 30 μM ZEA for 24 or 72 h in vitro. The results showed that ZEA exposure for 24 h remarkably reduced the proliferation of porcine granulosa cells in a dose-dependent manner as determined by MTT analysis and flow cytometry. Furthermore exposure to ZEA for 72 h induced apoptosis and RNA sequence analysis also revealed that the expression of apoptosis related genes were altered. RT-qPCR immunofluorescence and western blot analysis further confirmed the expression of DNA damage and repair related genes (γ-H2AX BRCA1 RAD51 and PRKDC) were increased in ZEA exposed granulosa cells. When the estrogen antagonist tamoxifen was added with ZEA in the culture medium the DNA damage and repairment by ZEA returned to normal level. Collectively these results illustrate that ZEA disrupts genome stability and inhibits growth of porcine granulosa cells via the estrogen receptors which may promote granulosa cell apoptosis when the DNA repair system is not enough to rescue this serious damage.