Proteomic analysis of selenium embryotoxicity in cultured postimplantation rat embryos.

BACKGROUND: Developmental toxicity of selenium (Se) is a nutritional, environmental and medicinal concern. Here, we investigated Se embryotoxicity by proteomic analysis of cultured rat embryos. METHODS: Rat embryos at day 9.5 or 10.5 of gestation were cultured for 48 or 24 h, respectively, in the presence of sodium selenate (100 or 150 microM) or sodium selenite (20 or 30 microM). Proteins from the embryo proper and yolk sac membrane were analyzed by two-dimensional electrophoresis for quantitative changes from those in control embryos. Proteins with quantitative changes were identified by mass spectrometric analysis. RESULTS: Growth inhibition and morphological abnormalities of cultured embryos were observed in all the Se treatment groups. By the analysis of the embryo proper, actin-binding proteins were identified as proteins with quantitative changes by selenate: increased phosphorylated-cofilin 1, increased phosphorylated-destrin, decreased drebrin E, and decreased myosin light polypeptide 3. Many proteins showed similar changes between selenate and selenite, including increased ATP-synthase, decreased acidic ribosomal phosphoprotein P0, and decreased pyrroline-5-carboxylate reductase-like. In the yolk sac membrane, antioxidant proteins were identified for protein spots with quantitative changes by selenite: increased peroxiredoxin 1 and increased glutathione S-transferase. CONCLUSION: The identified proteins with quantitative changes by selenate or selenite were considered to be candidate proteins involved in Se embryotoxicity: the actin-binding proteins for selenate embryotoxicity, proteins with the similar changes for the common Se embryotoxicity and antioxidant proteins for modification of Se embryotoxicity by redox-related treatments. These proteins may also be used as biomarkers in developmental toxicity studies.

Anti-hyaluronidase oligosaccharide derived from chondroitin sulfate a effectively reduces polyspermy during in vitro fertilization of porcine oocytes.

The present study was conducted to examine the effects of chondroitin sulfate A-derived oligosaccharide (ChSAO) on hyaluronidase activity and in vitro fertilization (IVF) parameters. The activity of hyaluronidase extracted from preincubated boar sperm was completely blocked by ChSAO at concentrations of 10 microg/ml or higher. After in vitro maturation of porcine cumulus-oocyte complexes, some oocytes were freed from their cumulus cells, and cumulus-intact or cumulus-free oocytes were inseminated with sperm in IVF medium containing various concentrations of ChSAO (0.1-100 microg/ml). In cumulus-intact oocytes, the penetration and the polyspermy rates (39% and 28%, respectively) were significantly decreased by treatment with 100 microg/ml ChSAO compared with those of oocytes treated without ChSAO (63% and 52%, respectively). On the contrary, in cumulus-free oocytes, the addition of 10-100 microg/ml ChSAO significantly reduced the polyspermy rate compared with the control (25-30% versus 53%, respectively), whereas ChSAO had no effect on sperm penetration. Interestingly, ChSAO added to IVF medium significantly decreased the number of sperm bound to the zona pellucida (ZP) of cumulus-free oocytes in a concentration-dependent manner between 0.1 and 100 microg/ml. However, ChSAO had no effect on the time course change in ZP modification after oocyte activation by electrostimulation and the incidence of the acrosome-reacted sperm. Treatment with 100 microg/ml ChSAO during IVF of cumulus-free oocytes significantly increased the proportion of development to the blastocyst stage after in vitro insemination. Therefore, the present findings indicate that hyaluronidase-inhibitory ChSAO is an efficient probe for promoting normal fertilization process in terms of an effective decrease in the incidence of polyspermy during IVF of porcine oocytes.