Prenatal Exposure to Soy Isoflavones Altered the Immunological Parameters in Female Rats

Soy Isoflavones Ameliorate Metabolic and Immunological Alterations of Ovariectomy in Female Wistar Rats: Antioxidant and Estrogen Sparing Potential

Hormone replacement therapy (HRT) can alleviate estrogen deficiency symptoms especially during menopause. The present study aimed at investigating the effect of soy isoflavones as HRT on immunological and bone health-related parameters with a special focus on the interactions between immunological status and metabolism. Thirty healthy cyclic female Wistar rats were used in this experiment. Ten females were sham-operated, and 20 females were subjected to ovariectomy. Overiectomized (OVX) female rats were randomly divided into 2 groups: the control group (G1, OVX/casein) was fed a casein-based diet, and the second group (G2, OVX/soy) was fed a high soy isoflavone diet. Both groups were compared to a sham-operated group (G3, sham/casein). Treatments continued for 7 weeks. Feed intake, weight gain, and lymphoid organ relative weights were recorded. Some metabolic, immunological, and bone health-related parameters were measured. Moreover, nitric oxide (NO), malondialdehyde (MDA), and total antioxidant capacity (TAC) were determined. Bone histopathology and immunohistochemistry to estrogen receptor alpha (ERα) were done. Feeding soy to OVX females reduced feed intake, weight gain, relative lymphoid organ weight, and T-lymphocytes transformation. Soy isoflavone administration normalized nearly all metabolic and immunological parameters to a level comparable to the sham group via oxidative stress amelioration and bone ERα promotion. Soy isoflavones seemed to be good HRT in estrogen deprivation which modulated the appetite, weight gain, lipid profile, proinflammation, and bone turnover.

Methylmercury promotes breast cancer cell proliferation

CONTEXT

Metalloestrogens are small ionic metals that activate the estrogen receptor (ER). Studies have shown that when metalloestrogens bind to the ER, there is an increase in transcription and expression of estrogen-regulated genes, which induces proliferation of estrogen-dependent breast cancer. Methylmercury (MeHg), a metalloestrogen, is present in the environment and is toxic at moderate to high concentrations. However, at lower concentrations MeHg may promote the proliferation of ER-positive breast cancers and protect cells against pro-apoptotic signals.

OBJECTIVE

To investigate the effects of MeHg treatment on breast cancer cells in vitro.

MATERIALS AND METHODS

MCF7 breast cancer cells were treated with concentrations of MeHg ranging from 1 nM to 100 mM. Hg analysis was used to quantify intracellular mercury concentrations. Cell proliferation and apoptosis were determined by cell counting and Annexin-V staining, respectively.

RESULTS

We defined a protocol that maximizes cellular exposure to mercury. Treatment of human ER-positive breast cancer cells with 1 nM MeHg promoted proliferation, while treatment with a concentration of 100 nM induced apoptosis.

DISCUSSION AND CONCLUSIONS

Clarifying the effects of MeHg on breast cancer will improve our understanding of how environmental toxins affect tumor progression and may lead to the development of future therapeutic strategies.

Dietary soy isoflavones during pregnancy suppressed the immune function in male offspring albino rats

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Less attention has been paid to the immune effects of phytoestrogens during pregnancy on the first generation.

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Soy isoflavones fed to pregnant rats could modulate the immune response of the male offspring.

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Isoflavones reduced spleen and thymus weights in rats born to dams fed dietary soy.

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Soy isoflavones possibly mediated its effect through reduction of IFN-γ that interacts with the IL-12 production pathway.

Phytoestrogens have an impact on both animals and humans due to use of legumes in animal diets as well as the increase of vegetarian diets in some human populations. Phytoestrogens thought to have varieties of adverse effects, among which immune system was involved. The present study aimed to investigate the effect of prenatal exposure to dietary soy isoflavones on some immunological parameters in male albino rat offspring. The pregnant rats were divided to three groups (12/group). Control group (free soy isoflavones), low soy isoflavones group (6.5%) and high soy isoflavones group (26%). The male offspring cell-mediated immune response was determined using phytohemagglutinin (PHA) injection and the intumesce index which was calculated on postnatal day 50 (PND 50). At PND 50, blood samples were collected for interleukin 12 (IL-12), interferon γ (IFN-γ) and tumor necrosis factor α (TNF-α) determination. Spleen, thymus, and PHA injected footpads were fixed for histopathology. Intumesce index, IL-12, IFN-γ, spleen and thymus relative weights were significantly (P < 0.05) decreased in offspring born to dams fed low and high dietary soy isoflavones. In contrary, TNF-α was significantly (P < 0.05) increased in offspring born to dams fed high dietary soy isoflavones. Spleen of rats born to dams fed high dose of dietary soy isoflavones showed coagulative necrosis in white pulp. In conclusion, male offspring born to dams fed different levels of soy isoflavones showed marked immunosuppression after PHA stimulation. This effect was mediated through the reduced IFN-γ that interacts with the IL-12 production pathway.

Isoflavones: Anti-Inflammatory Benefit and Possible Caveats

Inflammation, a biological response of body tissues to harmful stimuli, is also known to be involved in a host of diseases, such as obesity, atherosclerosis, rheumatoid arthritis, and even cancer. Isoflavones are a class of flavonoids that exhibit antioxidant, anticancer, antimicrobial, and anti-inflammatory properties. Increasing evidence has highlighted the potential for isoflavones to prevent the chronic diseases in which inflammation plays a key role, though the underlying mechanisms remain unclear. Recently, some studies have raised concerns about isoflavones induced negative effects like carcinogenesis, thymic involution, and immunosuppression. Therefore, this review aims to summarize the anti-inflammatory effects of isoflavones, unravel the underlying mechanisms, and present the potential health risks.