Cadmium-Induced Increase in Uterine Wet Weight and Its Mechanism

BACKGROUND: Cadmium (Cd) increases in uterine wet weight in rodents remain unclear and there are only a few studies that examined the effects of Cd on Uterine morphology It is unknown whether Cd induces a uterotrophic effect via its interaction with the estrogen receptor (ER). In our study, we compared the effects of cadmium chloride (CaCl2) on Uterine wet weight and morphology to those of 17 beta-estradiol in Sprague-Dawley (SD) rats. METHODS: Forty-eight SD rats (23 days of age) were ectomized and randomly divided into six groups (eight rats per group): vehicle control (sterile saline solution), positive control (17 beta-estradiol, 0.03 mg/kg in peanut oil), and CaCl2 groups (0.0064, 0.032, 0.16, and 0.8 mg/kg, respectively). The animals were treated by daily intraperitoneal (i.p.) injection for 3 days. The uteri were removed and assessed for weight, morphology, and immunohistochemical analysis. RESULTS: Compared to the control group, the Uterine wet weight, the thickness of endomerium, the thickness of the stroma and the nucleus/cytoplasm ratio in the 17 beta-estradiol-treated and 0.8 mg/kg-day CaCl2-treated groups changed (P < 0.01 or P 0.05). The endometrial gland number, the uterine epithelial cell height, and the PCNA-positive expression in 17 beta-estradiol-treated rats increased compared to that of the control (P < 0.01), but not in the CaCl2, dose groups. CONCLUSIONS: These results indicate that cadmium may induce in increase in uterine wet weight. However, this effect is not similar to that caused by 17 beta-estradiol, suggesting it is not via Ca-ER interaction. Birth Defects Res (Part B) 89:43-49, 2010. (C) 2010 Wiley-Liss, Inc.