A new way of animal control different from spaying and neutering; injection. But do not be fooled, for this injection is not like normal contraceptive shots. Through the works of Bruce Hay and Juan Li of the California Institute of Technology, they injected mice with foreign DNA so as they would produce antibodies that would attack reproductive hormones. The shot is administered into the muscles of the mice, which after two months resulted in infertile mice.
The main hormone that is targeted is gonadotropin-releasing hormone (GnRH). GnRH is produced in the brain and acts upon the pituitary glans to promote secretions to stimulate egg and sperm development. Juan Li, the first author, took the anti-GnRH gene and packaged it inside the shell of an aden-associated virus. This virus commonly infects mammals, but does not cause any symptoms. The manipulated virus is then injected into the muscles of the mice where the DNA is “unpackaged” and then used to create antibody factories. The benefit of injecting into the muscles is that muscle cells do not turn over. Therefore, the production of the wanted antibody will continue for years at a time as opposed to monthly injections like other birth control shot methods.
In addition to the injection, Hay and his lab blocked fertility in female mice using another antibody that binds to the protein layer called the zone pellucida, which surrounds the egg cells. This blocks the sperm from binding to the egg cells all the while not affecting the female hormonal cycle.
The importance of this process is that it saves time and money. Spaying and neutering feral animals includes the capture of the animal, anesthetizing the animal, performing the surgery on the animal, and then the time for them to recover.
The next question that comes along with this is can this be a new, permanent form of contraception for humans? The answer is not quite yet. As Hay puts it, “It’s a long road to develop any new drugs, but it might someday provide an alternative to current, surgical methods of permanent contraception.”
In the meantime this method is being tested with female feral cats in collaboration with Bill Swanson, Director of animal Research at the Cincinnati Zoo’s Center for Conservation and Research of Endangered Wildlife.
Personally, I feel that this would be a very effective way to population control in the animals that need it. In New Jersey (especially South Jersey), there is an awful deer population issue as well as an awful feral cat issue. Although hunting is a way to control deer, the cats keep reproducing even with the efforts of spaying and neutering the wild ones that can be captured. It amazes me how far genetic work has come to where scientists are able to take a virus and manipulate it then inject a gene that they want to be expressed into an animal. Also, the fact that this method could one day be used for humans is remarkable seeing as there would be no costly surgery involved.
