Immunomodulatory Effects of Estradiol and Cadmium in Adult Female Rats

Abstract

A wide range of toxic effects has been associated with cadmium (Cd) exposure in mammals. However, the physiological factors that modulate these effects have received limited attention. We have previously demonstrated that neonatal exposure of rats to Cd during lactation results in sex-specific immunotoxic effects in both juvenile and adult rats. The objectives of this study were to determine the effects of 17beta-estradiol (E(2)) on the immunotoxicity of Cd in female rats. We compared the effects of 28 days of exposure to 0, 5, and 25 ppm cadmium chloride (CdCl(2)) through drinking water on ovariectomized Sprague-Dawley rats and on ovariectomized rats with E(2) implant which mimicked the physiological level of E(2) in female rat. Our results clarify the control of important immune functions by E(2) at physiological level and demonstrate significant interactions between Cd and E(2) effects on the cytotoxic activity of natural killer cells and phagocytosis of splenic cells as well as on the total number of thymocytes and of the four subpopulations of the thymocytes as defined by the expression of the cell-surface markers CD4 and CD8. Cd and E(2) share several mechanisms of action that may account for these interactions. The estrogenic potential of Cd could also account for some of the observed effects. These interactions have to be taken into consideration in evaluating the risk of Cd immunotoxicity and the possible interactions with hormonal treatments.

The effect of dietary selenium supplementation on cadmium absorption and retention in suckling rats

“…According to Brzóska and Moniuszko-Jakoniuk (2005) treatment with these doses reflects real exposure level in moderately to heavily polluted areas, in active tobacco smokers or under occupational exposure conditions. Other authors used similar doses in their experimental designs Petersson Grawé et al 2004a;Fowler et al 2004;Pillet et al 2006). The total dose of Se (5.7 mg or 3.2 mg/kg body weight, Table 1) in our experiment was 54% or 30% the LD 50 dose, respectively, reported for adult female rats (WHO 1987).…”

Metals in human placenta: focus on the effects of cadmium on steroid hormones and leptin

“…The latter may involve a blending of the e ects of cadmium, ranging from in uences on protective mechanisms for prevention of placental-fetal rejection by the maternal immune system to the fetal response to antigen exposure in utero that can result in allergic disorders in early childhood. Steroid sex hormones are pleiotropic hormones that act on multiple targets, including their immunomodulatory role (Szekeres-Bartho et al, 2001;Pillet et al, 2006). Abnormal hormone levels can be closely related to genetic causes and factors related to infection that can trigger immune diseases and modulate their course (Vertheyli, 2001).…”

Effect of Daidzein in Rats on Cadmium Excretion

“…Phytoestrogens may competitively bind to an estrogen receptor with Cd. Hence, the inclusion of phytoestrogens in rodent diets might affect the outcome of bioassays designed to detect developmental toxicity or carcinogenity (Pillet et al, 2006).…”

“…Furthermore, Cd can also alter the hormonal balance and may exert estrogenic effects via interaction with ERs. Accordingly, Pillet et al (2006) suggest that females may be at a greater risk than males for Cd-induced immunomodulation.…”