In order to test the effect of porcine trophoblastic IFNs on the luteal cycle, two groups of cyclic Meishan gilts can-nulated in both uterine horns received injections of either a placebo (control group, n = 8) or increasing doses of a mixture of recombinant IFN-7 and IFN-8 (treated group, n = 7). Meishan gilts were used because they are presumed to be more sensitive to embryonic signals; indeed, after the transfer of 5 embryos into each Meishan gilt, the pregnancy rate was 58% compared to 33% for European hybrid gilts that also received 5 embryos each.
Injections were given with increasing doses twice daily for 4 days starting on Day 11 of the estrous cycle (see Table 1 and Materials and Methods section). Four controls and two treated gilts were eliminated from the experiment because one of the two uterine catheters emerged from the uterus and the injections were stopped during the experiment. These observations were confirmed at slaughter. In one of the two treated gilts and in the four controls that were eliminated, infection was observed near the utero-tubal junction at the exit of the uterine catheter and also on the abdominal wall near the exit of the uterine catheter on the flank. Among the eliminated controls, one did not return to estrus and had no ovulation. For the 9 other gilts, the uterine catheters were found in the uterus at slaughter and no infection was observed. Consequently, the number of animals in the control group and the IFN-treated group were 4 and 5, respectively. buy asthma inhaler
|Day of injection||IFN concentration in the mixtureIFN-7 IFN-8 Total IU/ml (jjLg/ml) (IU/ml X 10–3) X 10-3||Total IFN/horn/day(IU X 10-3)||Fold increase3|
a Approximate ratio between daily doses injected to cyclic gilts and doses found in pregnant uteri on the corresponding days of gestation. b Not determined.