The effects of neonatal Tamoxifen and Zearalenone exposure on histological features of uterus in mice

The uterus as the major female reproductive organ is particularly vulnerable to environmental and hormonal like compounds. Exposure to estrogen like disrupting chemicals during critical periods of development especially in the neonatal period can have adverse effects on reproduction and fertility later in life. In this study, the effects of neonatal exposure of mycoestrogen zearalenone and anti-estrogen tamoxifen on some histological characteristics of the uterus in female mice were investigated.
Material and 28 newborn female mice of BALB/c strain were divided into four groups (n=7): three experimental and one control group. Treatment Groups included Tamoxifen (400 μg /kg /day) group, group treated with zearalenone (2 mg /kg /day) and group treated with tamoxifen zearalenone. Control mice received no treatment. Daily treatments was started first day of life and continued up to 5 subcutaneously. Then about 70 days after birth in diestrous stage of estrous cycle, mice were deeply anesthetized and uterus was removed from the body. Following histochemical staining, the samples were studied using light and transmission electron microcopies.
The result of this study showed that in between the treatment groups, body weight decreased significantly (P>0.05) in group which received Tamoxifen, compared with control group. Uterus weight increased significantly in Zearalenone group (P>0.05) and Tamoxifen Zearalenone group (P>0.01). Endometrial thickness increased significantly (P>0.05) in group which received Tamoxifen and decreased significantly (P>0.05) in group which received Zearalenone. In addition, myometrial thickness decreased significantly (P>0.05) in group which received Zearalenone compared with control group. The study of electron microscopy showed that the number of cells of uterine luminal epithelial structure increased in the group treated with Tamoxifen compared with control group.
The result of present study indicates that neonatal administration of Tamoxifen and Zearalenone compounds cause histological lesions in uterus structure. Because of the estrogenic nature of zearalenone, the treated neonatal mice with this mycotoxin cause structural abnormalities especially in myometrial structure. On the other hand, Tamoxifen as an estrogenic agonist cause endometrial thickness increase and alterations in the uterus.