Sodium tungstate increases embryo implantation and reproductive efficiency in sprague-dawley rats

To evaluate sodium tungstate (ST) effects on reproductive outcomes in Sprague Dawley rats 8-9 week-old Crl:CD female rats were randomized into four groups. ST (40 (D1), 80 (D2), or 160 (D3) mg/kg/day) or vehicle were administered during at least 20 days, covering the premating period (14 days) until implantation of the conceptus (day 6 of gestation). After mating with competent males (ratio 1:1), mated females, confirmed by sperm presence in vaginal smears, were housed individually. Mated females were sacrificed on the 13th gestation day. Corpora lutea (CL) and implanted embryos (IE) were recorded. Implantations were classified as early intrauterine deaths, dead embryos, or viable embryos (VE). For groups comparison of fertility values ANOVA and Student's test were used. For comparison of percentages of success, a linear model with a binomial distribution using the "glm" function from the "stats" R [1] package was used. All mated females became pregnant in this study independently on the treatment dose or placebo. Evaluated fertility parameters are described in the table.Tabled 1Placebo (n=19)ST dose (mg/Kg/day)40 (n=18)80 (n=16)160 (n=19)Num. of CL16.7±1.517.3±1.517.8±1.3*16.6±1.4Num. of IE16.1±1.716.8±1.0#17.6±1.5**16.2±1.5Num. of VE15.3±1.916.1±1.1#17.1±1.7**15.7±1.6% of implanted embryos (IE/CL)96.5±4.697.7±4.198.9±3.3#97.7±3.8% of Implantation (VE/IE)95.1±4.995.8±4.497.0±4.297.2±5.1% of viable implanted embryos (VE/CL)91.7±6.593.6±7.096.0±5.9*94.9±5.5mean±SD. *p<0.05; **p<0.01; #p=0.06 Open table in a new tab Results show that despite the high fertility performance of the placebo group, ST enhances embryo implantation and the viability of implanted embryos with a statistical significance at D2 (11.8% and 9.3% increase of VE and IE respectively), and with a clear trend at D1 (5.2% and 4.3% increase of VE and IE respectively) when compared with placebo. No differences were observed between placebo and D3. Moreover, an increase in ovulation is observed only with D3. Implantation parameters normalized to CL show an increase in the percentage of viable implanted embryos (p>0.05) and percentage of implanted embryos (p=0.06). Additional analysis reveals that all embryos and females were healthy with no reprotoxic effects observed in any of the studied doses. Oral sodium tungstate treatment improves fertility in Sprague Dawley rats due to the direct effect of increasing embryo implantation. Additionally, it also enhances ovulation.