Cadmium: a toxicant with paradoxical effects on reproduction. preliminary results

Abstract

OBJECTIVE: Cadmium is one of the most important pollutants in industrialized countries, with potential mechanisms to affect steroidogenesis. This study aims to evaluate the correlation between cadmium levels in follicular fluid, semen and urine and the number of oocytes retrieved, metaphase II oocytes,embryos available, good quality embryos (≥ 8C G1/G2) and fertilization rate in couples undergoing ICSI cycles. DESIGN: Prospective cohort study. MATERIALS AND METHODS: From July to Dec 2009, 25 couples were enrolled after signing an informed consent. Women's age were ≤ 39.Follicular fluid (FF), semen and urine, were obtained on the day of retrieval. All samples were frozen at –20°C until being analyzed by electrothermal atomic absorption spectrometry. Standard occupational exposure Cd urine levels is ≥ 1.0 μg L−1. There are no reference values for FF and semen. RESULTS: The correlation between variables (Pearson's coefficient) in women presented a positive correlation between FF Cd levels (0.92 ± 0.19 μg L−1) and number of oocytes retrieved(r=0.42; p=0.0002); number of M II oocytes (r=0.51; p<0.0001) and the total number of embryos (r= 0.36; p=0.002). A negative correlation was observed between FF Cd and fertilization rate (r=-0.49; p< 0.0001). There was a positive correlation between urine Cd levels (0.28 ± 0.17 μg L−1) and the total number of good quality embryos (r= -0.32; p=0.008). A negative correlation was observed for semen Cd levels(0.21 ± 0.84 μg L−1) and the total number of embryos (r= - 0.46; p=0.001).No correlation was observed for urine Cd levels (0.28 ± 0.15 μg L−1) and the parameters analyzed. CONCLUSION: The intriguingly preliminary results of this ongoing study raise questions about paradoxical effects of cadmium concentrations that correlated positively with ovarian response (oocytes retrieved, MII oocytes and number of embryos obtained) and negatively with fertilization rate. Negative correlation between Cd semen and good quality embryos could be explained by DNA sperm fragmentation.