Guillermo Rimoldi

Effects of Chronic Genistein Treatment in Mammary Gland, Uterus, and Vagina

Background The isoflavone genistein (GEN) is found in soy (Glycine max) and red clover (Trifolium pratense). The estrogenic activity of GEN is known, and it is widely advertised as a phytoestrogen useful in alleviating climacteric complaints and other postmenopausal disorders. Knowledge of effects of long-term administration of GEN in laboratory animals is scarce, and effects in the uterus and mammary gland after long-term administration have not been studied. The uterus and mammary gland are known to be negatively influenced by estrogens used in hormone therapy. Objectives We administered two doses of GEN [mean daily uptake 5.4 (low) or 54 mg/kg (high) body weight (bw)] orally over a period of 3 months to ovariectomized (ovx) rats and compared the effects with a treatment with two doses of 17β-estradiol [E2; 0.17 (low) or 0.7 mg/kg bw (high)]. Mammary glands, vaginae, and uteri were investigated morphologically and immunohistochemically. We quantified the expression of proliferating cell nuclear antigen (PCNA) and progesterone receptor (PR) in the mammary gland. Results In rats treated with either of the E2 doses or the high GEN dose, we found increased uterine weight, and histologic analysis showed estrogen-induced features in the uteri. In vaginae, either E2 dose or GEN high induced hyperplastic epithelium compared with the atrophic controls. In the mammary gland, E2 (either dose) or GEN increased proliferation and PR expression. Serum levels of luteinizing hormone were decreased by E2 (both doses) but not by GEN. Conclusions In summary, E2 and GEN share many effects in the studied organs, particularly in the vagina, uterus, and mammary gland but not in the hypothalamo/pituitary unit.

Morphologic changes induced by oral long-term treatment with 8-prenylnaringenin in the uterus, vagina, and mammary gland of castrated rats.

Objective: The flavonoid 8-prenylnaringenin (8-PN) is found in hops, and hence in beer, and is also increasingly consumed as a food supplement. It is the strongest known phytoestrogen, which makes it a good candidate as an alternative to hormone therapy. Its putatively undesired estrogenic effects in the uterus and mammary gland have not yet been thoroughly investigated. Therefore, we performed a long-term oral administration experiment. Design: Rats were ovariectomized and fed for 3 months with soy-free chow containing estradiol (E2) or 8-PN, both in two doses (8-PN: 6.77 mg or 68.42 mg/kg body weight; E2: 0.17 mg or 0.7 mg/kg body weight) or no additives. Analysis was mainly focused on morphologic and immunocytochemical parameters. Expression of proliferating cell nuclear antigen as a proliferation marker and of progesterone receptor was quantified in the mammary gland. Results: Uteri of animals treated with both E2 doses and the high 8-PN dose had increased weight and showed histologic estrogen-induced features. 8-PN at the high dose induced epithelial polypoid formation unique to this group. Compared to the atrophic controls, both E2 doses and the high 8-PN dose induced hyperplastic epithelia in the vagina. The high doses of E2 and 8-PN caused secretion in the mammary gland, whereas proliferation and progesterone receptor expression were stimulated by both E2 doses and the high 8-PN dose. Conclusions: E2 and 8-PN share many effects in the three studied organs, but some differences in the mechanism of action appear to exist.

In Vitro Effects of Benzophenone-2 and Octyl-Methoxycinnamate on the Production of Interferon-γ and Interleukin-10 by Murine Splenocytes

Chemical ultraviolet light absorbers (UV-filters) are nowadays widely used in cosmetic and plastic industry. Recent in vitro and in vivo studies have reported that certain chemical UV-filters possess estrogenic activity raising the question of whether these compounds are safe to human health. Work on estrogenic effects of these compounds, however, has focused mostly on reproductive organs, and as the presence of estrogen receptors has been identified in several cells of the immune system, UV screens also may have a great impact on immunity. Thus, we have studied the in vitro effects of two widely used UV-filters—benzophenone-2 (BP-2) and octyl-methoxycinnamate (OMC)—on the production of interferon (IFN)-γ and interleukin (IL)-10, two cytokines representing Th1- and Th2-type response, respectively, by activated murine splenocytes. Cells were cultured on 48-well plastic plates and stimulated with 12-miristate 13-acetate (PMA) (5 ng/ml) and ionomycin (50 ng/ml) in the presence of different concentrations (10−5–10−8M) of the studied substances or 17β-estradiol (E2). After 48 hr incubation the supernatants were collected and the levels of IFN-γ and IL-10 were measured using immunoenzymatic assay. Our results show that BP-2 and OMC at high concentrations (10−5M) shifted the Th1/Th2 balance toward a Th2 response (lower IFN-γ production and higher IL-10). These effects were comparable to those of E2. Our results clearly show that UV-screens at high doses also may possess immunomodulatory effects some of which resemble those of E2.