The effects of soy extract on the uterus of castrated adult rats

Reproductive disorders in female rats after prenatal exposure to sodium arsenite

Arsenic is a metalloid widely found in the environment in organic and inorganic forms. Exposure to inorganic arsenic forms via drinking water has been associated with an increased incidence of negative health effects, including reproductive disorders and dysfunction of the endocrine system. However, the impact of arsenic exposure on female reproductive development is still unclear. Therefore, in the present study, we evaluated the effects of prenatal exposure to arsenic on the initial sexual development and puberty onset, and in the morphology of the female reproductive organs, estrous cycle regularity and fertility parameters during adulthood. To do that, pregnant female Wistar rats were exposed to 10 mg/L sodium arsenite via drinking water from gestational day (GD) 1 until GD 21 and the female offspring was evaluated in different postnatal days. Our results showed that prenatal arsenic exposure induced a decrease of litter weight and morphological masculinization in females at postnatal day 1. Moreover, these females had a delay in the age of puberty onset and alteration in estrous cycle number and length. During adulthood, females from the sodium arsenite group showed an increase in endometrium, myometrium and perimetrium areas, and an imbalance in uterine antioxidant enzyme activity. These animals also presented an increase in post-implantation loss and reabsorption number, leading to reduced viable fetus number. In conclusion, prenatal arsenic exposure in rats was able to promote female masculinization, alter sexual development and impair reproductive performance.

Sexual differentiation and reproductive development of female rat offspring after paternal exposure to the anti-tumor pharmaceutical cisplatin

Cisplatin (CP) is used to treat a number of cancers, including testicular cancer. Studies indicate that CP-treatment can impair spermatogenesis in humans and rodents by germ cell DNA binding, through different modes of action. CP-paternal exposure resulted in adverse effects in F1 male offspring. In this study, F1 female offspring was assessed for reproductive development after CP-paternal exposure. Peri-pubertal male rats, treated with 1mg/Kg/day of CP or vehicle for 3 weeks, were mated with unexposed females. F1 female offspring of CP-treated fathers showed a decrease in fetal ovary germ cells, in estrous cycle length and FSH levels, and an increase in the percentage of antral follicles in adults. Based on our previous results and the findings of the present work we concluded that CP-paternal exposure leads to adverse effects on rat male and female reproductive development, raising concern, in humans, for children born to men exposed to CP.

Do extracts of oral soybean augment the trophic effect of estrogen on the rat uterus?

OBJECTIVE

To evaluate whether soybean extracts and estrogens present additive effects on adult rat uterus.

METHODS

Fifty ovariectomized rats were randomly divided into five equal groups of ten animals: Control, treated with vehicle; SE46 and SE120, treated with 46 and 120 mg/kg soybean concentrated extract (SE), respectively; EE, treated with conjugated equine estrogens (CE) 50 μg/kg; SE120 + EE, treated with 50 μg/kg (CE) plus 120 mg/kg SE. The substances were administered daily by gavage for 21 consecutive days. Thereafter the animals were weighed and killed by decapitation; trunk blood was collected for hormone determinations. Uteri were removed immediately and fixed in 10% formaldehyde, followed by dehydration, embedding in paraffin and 6-m sections staining with hematoxylin and eosin for histomorphometric analyses of myometrium and endometrium. After ANOVA analysis of the data, the study was complemented with the Tukey-Kramer test for multiple comparisons.

RESULTS

The concentrated extract of soybean at high concentration (SE 120 kg/mg) and estrogens proved to have a trophic effect on the uterus (endometrium and myometrium) of castrated rats. In groups SE120, EE and SE120 + EE, all morphometric parameters examined (number of glands, eosinophils, blood vessels and the glandular area) were increased. No significant addictive effects of soybean extract plus estrogens were detected in the SE120 + EE group.

CONCLUSIONS

Our results indicate that soy extract has a trophic effect on rat uterine structures. Treatment of ovariectomized rats with a concentrated soy extract in combination with conjugated estrogens had no addictive effect on the uterine response.

The soybean concentrated extract proliferates the vagina of adult rats

OBJECTIVE

The aim of this study was to evaluate changes induced on the vagina of ovariectomized rats after treatment with soybean concentrated extract or conjugated equine estrogens and the association of both drugs.

METHODS

We conducted an experimental study with 50 ovariectomized rats that were randomly divided into five equal groups of 10 animals: GI received vehicle, GII received soybean concentrated extract 46 mg/kg per day, GIII received soybean concentrated extract 120 mg/kg per day, GIV received conjugated equine estrogens 50 μg/kg per day, and GV received conjugated equine estrogens 50 μg/kg and soybean concentrated extract 46 mg/kg per day. The substances were administered by gavage during 21 consecutive days. After that, the animals were killed under anesthesia and the vagina was removed for histological and immunohistochemical analysis. Data were initially submitted to analysis of variance. Whenever a significant difference was detected, the study was complemented with the Tukey-Kramer test for multiple comparisons.

RESULTS

GII did not show any differences on the vaginal epithelium or collagen compared with GI. GIII presented an increase in vaginal epithelium and collagen amount. GIV had the highest amount of collagen and the signals of vaginal proliferation. GV did not show any additional effect compared with GIV.

CONCLUSIONS

Our data suggest that a high dose of isoflavone-rich soy extract may have positive effects on the vaginal structures of ovariectomized rats, but this action is less than that of estrogen treatment on vaginal thickness. In addition, soy extract may not block the estrogen effect on vaginal tissue.

The effects of topical isoflavones on postmenopausal skin: double-blind and randomized clinical trial of efficacy

OBJECTIVE

The aim of this study was to evaluate the effects of estrogen and isoflavones on postmenopausal skin morphological parameters.

STUDY DESIGN

A randomized, double-blind, estrogen-controlled trial was performed on postmenopausal women treated in the Gynecology Department of the Federal University of São Paulo. This study was designed to analyze the effects of topical administration of estradiol and isoflavones on facial skin for 24 weeks. The participants were divided into two groups: G1-17-betaestradiol 0.01% (n=18) and G2-isoflavones 40% (genistein 4%, n=18). Skin biopsies were performed on each patient before and after the treatment. The skin samples were processed for histological analysis, stained with haematoxylin and eosin, and examined using light microscopy.

RESULTS

After 24 weeks of treatment, the estradiol group had a significant increase in skin parameters analyzed compared to the isoflavone group and to the baseline measurements: epidermal thickness (a 75% increase in the estrogen group and 20% in the isoflavone group), number of dermal papillae (a rise of 125% with estrogen, no significant gain with isoflavones), fibroblasts (a 123% accretion with estradiol, no significant gain with isoflavones), and vessels (a 77% increase with estrogen and 36% with isoflavones).

CONCLUSION

Our data suggest that estrogens may have a stronger effect on histomorphometrical parameters than isoflavones.

Effects of isoflavones on the skin of postmenopausal women: a pilot study

OBJECTIVE

The aim of this study was to evaluate the effects of isoflavones on the skin of postmenopausal women.

DESIGN

A prospective study was performed with 30 postmenopausal women before and immediately after the end of treatment with 100 mg/day of an isoflavones-rich, concentrated soy extract for six months. A skin punch was performed in the gluteal region for sample collection before and immediately after the treatment program. Morphometric determination of epidermal thickness, the papillary index (wrinkling), and the amount of dermal elastic and collagen fibers was assessed. In addition, the number of blood vessels in the sample was also evaluated. The paired Student's t-test was used for statistical analysis (P < 0.05).

RESULTS

Isoflavone treatment resulted in a 9.46% increase in the thickness of the epidermis in 23 patients. In addition, the papillary index was reduced in 21 women. The papillary index was inversely proportional to skin wrinkling, i.e., there were a large number of papillae after treatment. The amount of collagen in the dermis was increased in 25 women (86.2%). In 22 women (75.8%) we observed that the number of elastic fibers increased. The number of dermal blood vessels was significantly increased in 21 women.

CONCLUSION

Our data show that the use of a concentrated, isoflavone-rich soy extract during six consecutive months caused significant increases in epithelial thickness, the number of elastic and collagen fibers, as well as the blood vessels.

Proliferation of the superficial epithelium of ovaries in senile female rats following oral administration of conjugated equine estrogens

OBJECTIVE

To evaluate the effect of different concentrations of estrogen on the ovarian superficial epithelium in senile female rats.

DESIGN

Fifty female rats at 15 months of age and with irregular estrous cycles were selected and randomly divided into five experimental groups containing equal numbers of animals in each: GPROP, control group receiving vehicle only; GE0.05mg, group receiving conjugated equine estrogens (CEE) at a dose of 50 microg/kg; GE0.5mg, group receiving CEE at 500 microg/kg; GE1mg, group receiving CEE at 1 mg/kg; and GE2mg, receiving CEE at 2 mg/kg. The length of treatment was 21 days. After this period, the animals were anesthetized and the ovaries were fixed in 10% formaldehyde and processed for routine histology. Histomorphology was analyzed by light microscopy, and histomorphometrics were evaluated using the Imagelab program.

RESULTS

In the GPROP and GE0.05mg groups, the superficial epithelium of the ovary had a simple cuboidal shape, and as the estrogen dose increased, the epithelium thickened, with pseudo-stratified or stratified epithelium appearing in the GE2mg group. The animals in the group given the highest estrogen dose (GE2mg) showed the thickest ovarian epithelium and the largest perimeter and surface area of the surface ovarian epithelium (P < 0.01). However, the difference in epithelium thickness between the GE0.5mg and GE1mg groups was only slight.

CONCLUSION

Our data suggest that CEE at a dose of 2 mg/kg may induce marked proliferation of rat ovarian epithelium.