The Assisted Reproductive Technologies (ART) Core, directed by Dr. Calvin Simerly provides tools and expertise for ovarian stimulation, in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), embryo culture, and embryo transfer for pregnancy establishment, as well as natural matings. For primates, we principally use rhesus macaque oocytes and employ these various techniques to evaluate the fertilizing capacity of sperm, produce embryos at specific stages of preimplantation development and of different genetic reconstitution for pregnancy establishment. Frozen embryos at all stages of preimplantation development will also be available to augment the production of fresh material. Innovative techniques and application of protocols for investigating stem cell biology and ART methods can first be applied in rodents in a timely and cost-effective manner and once this technology is perfected, they can be translated to the more precious nonhuman primate that closely mimics events in humans. Methods of oocyte collection, in vitro fertilization, embryo production, transgenic approaches and the study of implantation in rodents are all relatively well established, providing a baseline of information to explore pregnancy outcomes before application to nonhuman primates. Studies in mice, rats, pigs, cows, and nonhuman primates are ongoing in the PDC ART Core facility.

In macaques, oocyte collection, in vitro fertilization by assisted reproductive technologies (ART) and embryo culture is well established (Figure 1A-D). Our ability to produce rhesus ICSI embryos, culture to the blastocysts and produce ART offspring is shown in Figure 4. We have perfected several different methods of assisted reproduction (Hewitson et al., 1999; Hewitson et al., 2002; Hewitson et al., 1998) and protocols for sperm freezing and artificial insemination (AI; (Gabriel Sanchez-Partida, 2000) in the rhesus monkey model. During the past four years, the ART laboratory has produced almost 40 macaque offspring using a variety of methods to assist investigators (Table I). Many of these animals, as well as offspring from other on-going pregnancies, are also available for analyses of imprinting status.

Figure 1. Rhesus embryo development after fertilization by intracytoplasmic sperm injection and the production of offspring by ART. A: 4-cell embryo, B: 16- to 32-cell embryo, C: morula, D: expanded blastocyst; E ‘pICSI’, conceived by ICSI using ejaculated sperm; F: ‘Icicle’, derived from an IVF embryo cryopreserved at the 8-cell stage; G: ‘Fraiser’, conceived after artificial insemination using frozen-thawed sperm.