Mice, Marrow, Mast cells... and Me


Photo: orange colored culture medium sits in the hood with other instruments at a Northwestern University lab.

by Anuja Vaidya/Medill News Service

My first instinct was to say no. I couldn't do it. It was a cute little mouse, white with a pink nose, just like the mice from "The Witches" by Roald Dahl. Except this one was dead and waiting to be cut open.

I was shadowing Maggie Walker, Ph.D candidate in the department of Microbiology-Immunology, as part of a requirement for one of my graduate school classes. Walker needed to grow mast cells for her research into their role in autoimmune diseases. She needed the bone marrow of mice so that she could culture the cells and use them to create mast cells. She had euthanized two mice and now needed to remove the bones from the legs.

She asked if I wanted to try it. I'd have to cut the leg, separate it from the body and then remove the skin and muscle tissue. It did not sound appealing.But then I stopped and thought. She wasn't asking me to bludgeon the mouse for no good reason. It was one small step towards understanding how to lessen the severe effects of diseases like multiple sclerosis.

"If our mouse work can at least narrow down the possibility of what's going on in human disease then that's an advancement in itself," said Julianne Hatfield, another Ph.D candidate in the lab.

When I asked my brother, who is a biologist, whether I should partake in the disturbing task, he said "What if mom had the disease they are working to prevent?"

Hatfield said that she couldn't imagine not using mice for experiments because it is more relevant than analyzing what's happening in a petri dish.

So I decided to try and be cool, scientific and have an experience that is unlikely to come my way again.

I put on white gloves, steeled myself and approached the hood, which is the large, rectangular box-like structure where mice can be dissected in a sterile environment. It has steel walls on three sides and glass halfway down the fourth side. You sit in front of it, put your hands under the glass and get to work.

I held the mouse down with my tweezers.The first step was hard, particularly because it was still a mouse that looked as if it were sleeping. I took a deep breath, concentrated just on its leg and started cutting. It became easier with every step. Once we had focused on the leg and the mouse itself was taken away from the table, it became easier to concentrate.

I've heard people say that human beings are incredibly visual. I now realize just how much. Once it stopped looking like something I recognized, I didn't feel as squeamish.

I asked Craig Smuda, a dual M.D/Ph.D candidate in the lab, why mice are used so widely in research.He told me that mice have short lives, breed quickly and are close enough to humans that the insights you get from researching with mice can lead to insights into human medicine.

The last step of the process was the most challenging. It involved drilling tiny holes into both sides of the leg bone and then injecting culture medium, which is a mixture of liquid substances in which cells and tissues can be grown. The culture medium is shot through each end of the bone so that the marrow is forced out from both sides. This was so precise and difficult that I found myself obsessed with getting it right. I struggled to hold the tiny bone still while trying to inject the medium. The bone kept slipping from my tweezers. I was half afraid that I'd end up injecting myself. In the end, I did manage to extract some marrow.

With mixed emotions - the flush of success, the shock that I had actually done it and the discomfort with the more gruesome aspects - I helped wipe down the hood.

"I work with animals as a necessary thing," Smuda said to me later, "What I'm doing to them might harm them but I try to cause them as little pain as possible while at the same time achieving my goal."

That helped balance things out in my mind. It isn't a pleasant experience cutting into a dead mouse, but it is necessary for advancements in medicine and science. Trying to make it as painless as possible for the animal is about the best that scientists can do.




Interesting article. I have peripheral neuropathy and have been told that my immune system attacks the sheathing of my nerves. Could the work being done by Maggie and others at Northwestern be helpful for my problem? Thank You - Michael Buchanan in Ft. Worth, Texas

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