The Fall 2009 Oncofertility Consortium’s Virtual Grand Rounds hosted Dr. David Wildt of the Center for Species Survival at the Smithsonian National Zoo for his talk entitled “Sex, Wildlife and Intensive Management”. Joining him in giving this seminar were Dr. Nucharin Songsasen and Dr. Pierre Comizzoli, also of the National Zoo. Dr. Wildt began by addressing the role of the reproductive sciences in wildlife management and the challenges faced in this field. One of the main challenges is the lack of knowledge that is compounded by the incredible diversity that exists. For example, of 5500 mammalian species, only about 100 have been studied with respect to reproductive biology. This is partially reflected in the reproductive biology literature: approximately 10% of publications in the field relate to wildlife, compared to 36% relating to the “role model” species, rodents and cattle. Of the species that have been studied, there are great differences in reproduction. To illustrate this, Dr. Wildt described both the Great Pandas which spend less than 1% of their lives in estrus, the time it is possible for them to become pregnant, and bats which have the capability of storing sperm, not just for days or weeks, but for months! This diversity can also be found within species such as canids: the domestic dog has spontaneous estrus with no seasonality however, the Maned Wolf only ovulates in the first half of the year and only in the presence of males. Dr. Wildt talked at length of how the information gathered is put to practical use in species management, as well. In 1996, Dr. Wildt was part of a multidisciplinary team that went to China to work on reversing the stagnation of the panda population. By applying the knowledge gained from this research team, the number of pandas (in captivity) has been increased from 104 in 1998 to 292 in 2009. Soon this population will be self sustaining and reintroduction of pandas to the wild will commence. Dr. Wildt stressed that reproductive science is more than just ARTs and that often species management can be done purely by understanding the factors that affect an animal’s fertility, such as environmental influences. For example, switching from small cages to a more natural enclosure lowered the stress of a colony of Clouded Leopards in Thailand, enabling natural reproduction to occur.
Dr. Wildt then turned it over to his colleagues Dr. Songsasen and Dr. Comizzoli to describe what is on the horizon for reproductive sciences in wildlife and species management. Dr. Songsasen and Dr. Comizzoli updated us to the latest advances at the bench using the domestic dog and cat as models for wild canids and felids, respectively. These species are important because they can serve as a model for many human diseases such as diabetes, retinitis pigmentosa and cancer. There are also parallels with humans and fertility. For example, teratospermia is seen in cats with very high frequency (~60%). Dr. Songsasen described her work with the domestic dog and the successes with in vitro follicle culture. Using the alginate culture system developed by the Woodruff lab, preantral follicles can be cultured and demonstrate hormone production. Dr. Songsasen discussed the impacts of including various additives to the culture system including FSH and LH and also how the age of the animal affects the culturing. Dr. Comizzoli then went on to describe his work with in vitro maturation of domestic cat oocytes and with vitrification of ovarian tissue. Upon thawing of cortical strips, they are able to demonstrate that about 80% of the original structure is preserved and about 70% of the primordial follicles are viable.
Thanks to Drs. Wildt, Songsasen, and Comizzoli for excellent examples of how non-typical animal models can be used for oncofertility research, and the ways we can pay these animals back by using our findings to help sustain their populations!
The presentation will be posted for viewing here within the next few days!