Gestational Zearalenone Exposure Causes Reproductive and Developmental Toxicity in Pregnant Rats and Female Offspring

Abstract

Zearalenone (ZEN) is an oestrogenic mycotoxin commonly found in food and feed products and can affect reproduction and development in both humans and animals. This study aimed to determine the toxic effects of ZEN on maternal SD rats and the F1 female offspring. Sixty-four pregnant rats were divided into 4 groups and exposed to feed contaminated with ZEN (0, 5, 10, and 20 mg/kg feed) on gestational days (GDs) 0-21. Compared with the controls, the groups exposed to 10 and 20 mg/kg ZEN showed significantly decreased feed intake and body weight of pregnant rats and/or female offspring. Meanwhile, 20 mg/kg ZEN significantly decreased the birth weight and viability of F1 newborn rats. Moreover, 10 and 20 mg/kg ZEN diets increased follicle-stimulating hormone concentrations but decreased oestradiol in both maternal and F1 adult rats. In the F1 generation, ZEN caused no pathological changes in ovaries and uterus in weaned rats, but significant follicular atresia and a thinning uterine layer were found in F1 female adult rats in the 20 mg/kg ZEN group. These impairments concurred with the inhibited mRNA and protein levels of oestrogen receptor-alpha (Esr1) and 3β-hydroxysteroid dehydrogenase (HSD) in the adult uterus and/or ovaries. Furthermore, 10 and/or 20 mg/kg ZEN exposure significantly reduced Esr1, gonadotropin-releasing hormone receptor (GnRHr), and ATP binding cassette transporters b1 and c1 (ABCb1 and ABCc1) in the placenta and foetal and weaned F1 brains, and also produced a dose-dependent increase in 3β-HSD in the placenta. Additionally, 20 mg/kg ZEN significantly upregulated ABCc5 expression in the placenta and ovaries of weaned rats. These results suggested that prenatal ZEN exposure in rats affected maternal and foetal development and may lead to long-term reproductive impairment in F1 adult females.

Keywords: F1 female rats; gestational exposure; transgenerational toxicity; zearalenone.

Figure 1

Effects of prenatal ZEN exposure on ovaries of F1 weaned and adult female rats. The hepatic sections were stained with haematoxylin and eosin; photomicrographs are shown at 100 or 200× magnification. Weaned ovaries: (A–D) adult ovaries: (E–H) ZEN, zearalenone; Control, 0 ZEN diet; 5 ZEN, 5 mg/kg ZEN diet; 10 ZEN, 10 mg/kg ZEN diet; 20 ZEN, 20 mg/kg ZEN diet.

Figure 2

Effects of prenatal ZEN exposure on uterus of F1 weaned and adult female rats. The hepatic sections were stained with haematoxylin and eosin; photomicrographs are shown at 100 or 200× magnification. Weaned uterus: (A–D) adult uterus: (E–H) ZEN, zearalenone; Control, 0 ZEN diet; 5 ZEN, 5 mg/kg ZEN diet; 10 ZEN, 10 mg/kg ZEN diet; 20 ZEN, 20 mg/kg ZEN diet.

Figure 3

Effects of prenatal ZEN exposure on relative mRNA abundance of hormones-related genes or ABC transporters in placenta, foetal brain, and weaned F1 tissues. Values are means ± SD, n = 12. ^a,b,c Means without a common letter differ, p < 0.05. ZEN, zearalenone; Esr1, oestrogen receptor alpha; GnRHr, gonadotropin-releasing hormone receptor; 3β-HSD, 3β-hydroxysteroid dehydrogenase; ABCb1, ATP binding cassette transporters b1; ABCc1, ATP binding cassette transporters c1; ABCc5, ATP binding cassette transporters c5. (A) Placenta; (B) foetal brain; (C) weaned F1 brain; (D) weaned F1 uterus; (E) weaned F1 ovary.

Figure 4

Effects of prenatal ZEN exposure on relative mRNA abundance of hormones-related genes or ABC transporters in brain, uterus, and ovary in adult female F1 rats. Values are means ± SD, n = 12. ^a,b,c Means without a common letter differ, p < 0.05. ZEN, zearalenone; Esr1, oestrogen receptor alpha; GnRHr, gonadotropin-releasing hormone receptor; 3β-HSD, 3β-hydroxysteroid dehydrogenase; ABCb1, ATP binding cassette transporters b1; ABCc1, ATP binding cassette transporters c1; ABCc5, ATP binding cassette transporters c5. (A) Adult F1 brain; (B) adult F1 uterus; (C) adult F1 ovary.

Figure 5

Effects of prenatal ZEN exposure on protein expressions of 3β-HSD and Esr1 in ovaries and uterus in adult female F1 rats. Values are means ± SD, n = 6. ^a,b,c Means without a common letter differ, p < 0.05. ZEN, zearalenone; Esr1, oestrogen receptor alpha; 3β-HSD, 3β-hydroxysteroid dehydrogenase. (A) 3β-HSD expressions in adult F1 ovaries; (B) Esr1 expressions in adult F1 ovaries; (C) 3β-HSD expressions in adult F1 uterus; (D) Esr1 expressions in adult F1 uterus.