A single intrauterine infusion of sustained recombinant ovine interferon-τ extends corpus luteum lifespan in cyclic ewes

Abstract Delivery carriers were developped to permit sustained release of recombinant ovine tau-interferon (roIFN-τ) to increase corpus luteum (CL) lifespan in cyclic ewes following a single intrauterine administration on Day 10 post estrus. A single infusion with 1.7mg roIFN-τ covalently bound to carboxymethyl biogel agarose (carbodiimide coupling) significantly increased the interestrus interval (P 0.05). These results are consistent with previous data from experiments performed with daily intrauterine infusion of soluble, native or recombinant oIFN-τ. In addition, because CL maintenance requires only a single administration, these methods are efficient and simple to use since they avoid animal catheterization and allow for reduced injection frequency. Moreover, they may permit the use of smaller amounts of IFN. It is concluded that the use of oIFN-τ sustained in some delivery systems may allow for the development of an experimental sheep pseudopregnancy model.