Morfofunkcionalne osobine reproduktivnog sistema nezrelih i acikličnih ženki pacova nakon tretmana fitoestrogenima iz soje

Abstract

Fitoestrogeni iz soje, pre svega genistein i daidzein, su veoma zastupljeni u životu savremenog čoveka, kako kroz ishranu, tako i kroz pomoćna lekovita sredstva. Zbog svog selektivno modulatorskog, tj. tkivno specifičnog estrogenskog delovanja, fitoestrogeni poslednjih godina postaju atraktivno polje intenzivnih studija. Period gašenja reproduktivne funkicije kod žena, tj. menopauza, vrlo često je praćen tegobama i poremećajima koje su posledica smanjenja koncentracije endogenog estradiola, odnosno funkcije ovarijuma. Stoga je jedna od mogućih terapijskih aplikacija genisteina i daidzeina upravo sprečavanje i ublažavanje ovih tegoba, a kao alternativa supstitucionoj hormonskoj terapiji. Međutim, njihovo delovanje na organe ženskog reproduktivnog sistema, naročito u periodu menopauze, još uvek nije u potpunosti istraženo. Cilj ove studije obuhvata rasvetljavanje dejstava fitoestrogena na reproduktivni sistem nezrelih i acikličnih ženki pacova. Od posebnog interesa je jasno definisanje potencijala fitoestrogena u poboljšanju funkcije reproduktivnog sistema u animalnom modelu menopauze, kao i poređenje efekata njihove aplikacije sa onima koje ima aplikacija terapijske doze estradiol dipropionata, koji se koristi kao lek izbora u prevenciji i terapiji menopauzalnih simptoma. Za ispitivanje estrogenske aktivnosti fitoestrogena (genisteina i daidzena) korišćen je uterotrofni esej po protokolu Organizacije za ekonomsku saradnju i razvoj (OECD). Ženkama pacova starosti 19 dana aplikovani su fitoestrogeni (genistein i daidzein), tokom tri dana u tri doze (visokoj, srednjoj i niskoj). U okviru protokola predviđene su i kontrolne grupe - pozitivne kontrolne grupe, koje su primale 17α-etinil estradiol (u dve doze), negativne kontrolne grupe koje su primale rastvarače, kao i intaktna kontrolna grupa. Nakon uterotrofnog eseja, utvrđeno je koja doza fitoestrogena (genisteina i daidzeina) ispoljava minimalan estrogenski efekat. Ta doza je, tokom četiri nedelje, aplikovana acikličnim ženkama pacova starosti 12 meseci, koje predstavljaju eksperimentalni model menopauze. Na ovaj način utvrđeno je da li ispitivani fitoestrogeni (genistein i daidzein) imaju efekat na strukturu i funkciju organa reproduktivnog sistema, hipofize, ovarijuma, uterusa i vagine. Dodatno su efekti fitoestrogena poređeni sa efektima koje u organima reproduktivnog sistema izaziva terapijska doza estradiol dipropionata. Promene u strukturi i funkciji organa reproduktivnog sistema analizirane su histološkim, imunofluorescentnim, savremenim stereološkim, morfometrijskim i molekularno biološkim metodama. Imunofluorescentno obeležavanje specifičnih antigena, omogućilo je vizuelizaciju gonadotropnih i laktotropnih ćelija hipofize, i izračunavanje relativnog intenziteta fluorescentnog signala. Istim metodama, detektovano je i prisustvo laktoferina, kao i steroidnih receptora u uterusu nezrelih i acikličnih ženki pacova...

Soy phytoestrogens, primarily genistein and daidzein, are widely used through diet and as dietary supplements. Since they may act as “natural” selective modulators of estrogen receptor, scientific interest for phytoestrogens is constantly increasing. Cessation of a women’s reproductive function, i.e. menopause, is often accompanied with disorders that are consequence of reduced ovarian function and low estrogen concentration. Therefore, one of the possible therapeutic application of genistein and daidzein is prevention and alleviation of menopausal symptoms, as an alternative to hormone replacement therapy. The aim of this study is to examine the effects of phytoestrogens on the reproductive system of immature and middle-aged female rats. Of particular interest is to define the potential of phytoestrogens for improvement of reproductive system function in an animal model of menopause, and to compare these effects with the effects of therapeutic doses of estradiol dipropionate, commonly used in prevention and treatment of menopausal symptoms. Uterotrophic assay was used in order to test estrogenic activity of genistein and daidzein, according to the protocol of the Organization for Economic Cooperation and Development (OECD). Immature female rats received phytoestrogens (genistein and daidzein), in three doses (high, medium and low) for three consecutive days, from 19th till 21st day of life. According to the protocol, control groups were formed - the positive control groups that received 17α - ethynyl estradiol (in two doses), negative control groups that received solvents, and the intact control group. After uterotrophyc assay, minimal dose of genistein and daidzein that exerts estrogenic effect was determined. This dose was administered to 12 months old, middleaged female rats, for four weeks. After this period it was analyzed whether genistein and daidzein exerted beneficial effects on the structure and function of the pituitary, ovary, uterus and vagina. These effects were then compared with the effects of the therapeutic dose of estradiol dipropionate. Changes in the structure and function of the organs of reproductive system of immature and middle-aged female rats were analyzed by histological, immunofluorescence, design-based stereological, morphometric and molecular biological methods. Immunofluorescent labeling of specific antigens allowed the visualization of the pituitary lactotropic and gonadotropic cells, and the calculation of the relative intensity of fluorescent signal, i.e. concentration of antigen within the cell. In the same manner, the presence of lactoferrin and steroid receptors in the uterus of immature and middle-aged female rats was analysed...