Assessment of oocytes retrieved from stimulated and unstimulated ovaries of pig-tailed macaques (Macaca nemestrina) as a model to enhance the genetic diversity of captive lion-tailed macaques (Macaca silenus)

Abstract

Steroid hormone levels were measured during unstimulated menstrual cycles of pig-tailed macaques (Mucucu nemestrina) and lion-tailed macaques (Mucucu silenus). The values were similar, suggesting that the pig-tailed macaque may be an appropriate model for in vitro fertilization and embryo transfer in the lion-tailed macaque.Two follicular stimulation protocols were compared to evaluate the yield and quality of the oocytes obtained from pig-tailed macaques. Five animals received a regimen of PMSG (Protocol I) and five received a regimen of Pergonal (Protocol 11). Oocytes from natural cycles were obtained from seven pig-tailed macaques during 21 cycles. If the oocytes extruded a polar body, they were inseminated and then observed for penetration and cleavage. Oocytes that produced quality embryos were transferred to recipient pig-tailed macaques or rhesus macaques (Mucuca muluttu).Oocytes from natural cycles had a higher percentage of good embryos produced from inseminated eggs (22.7%) compared to Protocol I (10.3%) or Protocol I1 (14.2%). However, Protocol I and Protocol II yielded more quality embryoskycle (2.0, 1.4, respectively) than natural cycles (0.24). Pig-tailed macaques were refractory to a second PMSG protocoI, but Pergonal and natural cycles could be repeated on the same individual before or after PMSG. A total of 12 embryos were transferred to six pig-tailed macaques and three rhesus macaques during natural or stimulated cycles. No pregnancies resulted. Refinement of IVF-ET

In Vitro Manipulation of Nonhuman Primate Gametes for Embryo Production and Embryo Transfer.

“…Among the several types of media reported, my research group selected TYH medium [103], which was developed for IVF of mouse eggs. Furthermore, by incubation of the spermatozoa in medium that contained caffeine and dibutyryl cyclic AMP, sperm capacitation and hyperactivated motion were induced in spermatozoa of the rhesus monkey (Macaca mulatta) [11], the pig-tailed monkey (Macaca nemestrina) [18], and the cynomolgus monkey [5,56]. Our study also confirmed this finding in cynomolgus monkeys [84], Japanese monkeys [83], and African green monkeys (Cercopithecus aethiops) [78].…”

In vitro fertilization‐embryo transfer in nonhuman primates: The technique and its applications

“…In contrast, there is a species specificity for primate LH in follicle/ oocyte maturation and ovulation (Knobil et al, 1959;van Wagenen, 19681, since LH-CG receptors in monkeys (Cameron and Stouffer, 1981) and humans (Berman and Sairam, 1983) have a much higher affinity for primate, as compared to nonprimate gonadotropins. Thus, it is possible to stimulate the growth of numerous follicles in macaques by a PMSG regimen beginning around day 3-5 of the cycle, followed on day 16 by a primate LH-like preparation (hCG) for ovulatory maturation (Bavister et al, 1983Boatman et al, 1986;Cranfield et al, 1989;Fujisaki et al, 1989). Nevertheless, problems addressed in the section on limitations restrict this protocol's usefulness, particularly in endangered species.…”

“…Variable-dose, individualized regimens of gonadotropins, presently common in clinical IVF-ET programs (Jones, 19851, were employed 20 years ago to induce single ovulations in bonnet mon- keys (Ovadia et al, 1971). Recent results, although preliminary, suggest that individualized protocols could aid in achieving a greater incidence of hyperstimulation and the desired numbers of oocytes in nonhuman primates (Cranfield et al, 1989). Since hMG preparations contain both FSH-and LHactivity, both gonadotropins may be promoting the growth and maturation of multiple follicles.…”

“…However, noninvasive methods to monitor follicle growth and maturation have been developed with the goal of identifying animals that a) should be discontinued ) o r b ) have their protocol individualized to achieve an adequate response (Cranfield et al, 1989).…”

“…One hyperstimulation protocol with PMSG produces neutralizing antibodies in rhesus monkeys that prevent further ovarian stimulation by this gonadotropin . Likewise, pig-tailed macaques (Cranfield et al, 1989) and squirrel monkeys (Dukelow and Vengesa, 1986) rapidly become refractory to PMSG treatment. Human gonadotropins in rhesus or cynomolgus macaques also elicit antibody production (Platia et al, 1984;Rotten et al, 1986;Wolf et al, 1989).…”