Supervisors info:
ΣΤΑΜΑΤΑΚΗΣ ΑΝΤΩΝΙΟΣ, ΑΝΑΠΛΗΡΩΤΗΣ ΚΑΘΗΓΗΤΗΣ, ΝΟΣΗΛΕΥΤΙΚΗ, ΕΚΠΑ
Summary:
Endocrine Disrupting Chemicals (EDCs) are chemical substances that can enter in the organism and disrupt the function of the endocrine system. One category of EDCs, phthalate esters or phthalates, are commonly used in the manufacturing of plastic and personal-care products and seem to be involved in the development of various types of disease. Studies suggest that one target of phthalate action is the reproductive system, which plays an important role in physiology mainly by producing gametes and synthesizing and secreting steroid hormones.
The deeper understanding of phthalate mechanism of action, is one of the goals of EDC-MixRisk Program, in which researchers from Europe and the USA are collaborating in order to ensure safer living conditions for future generations. The laboratory of Basic Biomedical Sciences of the Department of Dentistry (National and Kapodistrian University of Athens), as a partner of EDC-MixRisk Program, studies the impact of neonatal exposure to endocrine disruptors in mice.
Within the framework of this study, basic parameters that are influenced by the in utero exposure to phthalates’ mixture, were assessed. These included: body weight in different developmental stages, anogenital distance (AGD) and vaginal opening used as an external index of puberty onset. In addition, in order to examine the impact of the mixture S0 on the basic organ of female reproductive system, the ovary, morphometric, histological and biochemical analysis were conducted in prepubertal and adult ovaries. Our objective was to determine the number and morphology of the ovarian follicles, along with the expression levels of the receptor FSHR, which mediates the signaling of a very important hormone of the female reproductive system, follicular stimulating hormone (FSH).
The results of our study, suggest that the in utero exposure of female mice to a mixture of phthalate esters, causes reduction of body weight during pre-puberty and changes of the anogenital distance, during neonatal life and pre-puberty. These results indicate that phthalate esters interfere with the normal function of metabolism and the development of secondary sex characteristics. On the other hand, they didn’t seem to cause changes on the day of vaginal opening, a characteristic which is affected by other endocrine disruptors.
Concerning the ovary, even though its weight did not seem to change after the exposure to the phthalate mixture, many changes were caused in the ovarian histology. Specifically, morphometric study of ovarian sections, showed increased follicle atresia. The importance of the atresia was shown in the adult ovaries, where follicles of early developmental stages (primary and secondary) were significantly reduced. This reduction means a decrease in available follicles for future ovulations, a sign of premature ovarian failure.
During our study, we also observed ovarian cysts in females exposed to the mixture S0. Ovarian cysts have been linked with the occurrence of Polycystic Ovarian Syndrome (PCOS) in humans, a very common disease of female reproductive system nowadays. It has also been considered a sign of reproductive senescence.
In total, our results indicate that endocrine disrupting chemicals, such as phthalate esters, interfere with normal development and function of female reproductive system, setting the bases for the occurrence of various diseases. These findings enhance the notion that phthalates pose a severe danger for human health and for all living organisms and that many efforts should focus on the restriction of their use and their replacement from other, safer chemical substances.
Keywords:
Endocrine disruptors, EDCs, female, reproduction, ovary, mouse
