Infanticide

So, it's 4 am, and I'm still awake so why not post about research?

When doing the rat reproduction trials, we encountered a scary problem: infanticide. This is the term applied to mothers who eat their babies. It has been linked to many causes, including cages that are cleaned too frequently, causing the mother to not recognize their smell. Our cages were changed only once the pups had fur, so I discount that explanation. Also, a lot of the pup-eating moms ate their newborn or 2-day-old pups. The cages were not changed or cleaned at that early of a time. Another theory as to why mom's eat their pups is that they can only feed a certain number of pups, so they eat a couple to ensure food for the other, supposedly more fit pups. I think this may be true in some scenarios, especially when there was a stillborn pup or two in the litter, however some moms ate all 10 or so of their pups. It was disgusting. This leaves the last, and most probable theory: the mothers were stressed, so they ate their pups to save energy for a new litter under less stressed conditions. It's true that when word got out that my experiment worked, EVERYONE came to ogle the pups, even when I was not there. I put up a sign on the door saying to be quiet, but I've caught colleagues chit chatting in the pup room. I was not happy. Also, I am required to spend a lot of time in that room myself, just feeding them because they eat a ton of food every day and I have over 60 cages to refill food and water. This takes a while.

FYI that painting is by Spanish painter Francisco de Goya, and it's called Saturn Devouring His Son

Ratlets pups and stillborn

I really have no time right now to write, I need to be at work, but incase I forget to update: PUPS HAVE BEEN BORN!! So you can house 2 female rats and one male and get pups, our protocol worked!

Also, sadly #16 died yesterday shortly after giving birth to ten stillborn pups. They looked like regular pups from the arms up, but below were some malformations. It was a sad sight to see, the mother surviving her pups for a day, then dying in the nest she had made for them. I will get back to how this may have happened, why, and what it means in the future.

Caffeine

My friend in the lab is doing small dose caffeine injections to determine the neuroprotective effects of the molecule. Specifically, we are seeing whether it helps stave off diabetes mellitus type 2 on adult mice that are given a high fat diet.

High fat diets will cause diabetes, that is indisputable. Caffeine or coffee has been linked with a reduced risk developing diabetes. The argument is whether it is the coffee bean's chemistry or the caffeine molecule in particular that is helping. Some studies show decaff coffees give more benefit than caffeinated, and some show that caffeine helps more than decaff. This will be a conundrum until somebody finally figures out the molecular pathways linking diabetes and coffee.

Rat Love

The second part of my experiment began last week. I am testing whether or not the high fat diet affects female fertility. I have read some studies before discussing how higher fat content makes pregnancies more difficult to progress without complication, but I think this is the first of its type.

I have 48 female rats, 12 controls and 36 rats fed on diets of differing fat content. I have 13 males that are fed standard rodent chow, and I'm putting them each in a cage with the females overnight. The females are housed 2 per cage now, because it no longer matters whether they are cycling together. Rats are nocturnal,so the males are put in at night when they are most active. Also, I take the food out for the night because I don't want the male rats to be eating the high fat diet, especially since the same male rats will be used for control and experimental trials. I hope this arrangement works, we have a tight budget and not a lot of room for error. I would also be interested in seeing whether high fat diets during pregnancy affect the pup's cognition after birth. However, I will be graduating in December, so maybe I could give my experiment to another researcher.

OK, time to change cages :X.

STZ: the aftermath

Last week, one of our researchers found herself in trouble. She begins her PhD program in another school, another state, and her admission is contingent upon completing a thesis. Her experiment is on diabetes type 2 on mice, but we needed them to be diabetic quickly so she can do her experiment and graduate. The standard protocols for mice with type 2 are few and far between. Usually, you just give them a diet very high in fat and wait for them to become diabetic. This can take upwards of 6 months after the diet begins. With time being the main issue, only a month left and no diabetic mice, we had to look for a new approach. (you can buy mice that are diabetic, but that was 'too expensive' according to our advisor).

I found an article published within the past 5 years, from Shanghai, China showing that you could induce type 2 diabetes with a drug called stroptozotocin (STZ). STZ is not a new thing for me; I know it wipes out pancreatic beta cells and is commonly used in rats to make type 2 diabetes, and in mice and rats to make type 1 diabetes (they just give the injection much earlier).

Here's the link: http://biomedicum.ut.ee/sjlas/34_1_22-29.pdf

The paper claims that a high dose of STZ on fat fed mice (of the same strain as ours) will become diabetic after the administration of one large dose of STZ. We replicated the study as best we could, since it was improvisation we had a high fat diet, but not as high as theirs and our mice were older than theirs by 2 weeks.

Injection day came, and the STZ was put into solution and injected IP (intraperitonial), to which the mice responded by jerking around and slowing down. They were losing control of their muscles. By the next day, we were down 16 mice, all of the mice that were injected died, except one. The researcher was distraught to say the least, and I couldn't help but feel guilty for suggesting that paper.

This past week, we have been experimenting with dosage, staggering injections by giving 1/4 of the dose for 4 days, and trying to make the drug less potent. So far, no luck. The researcher has to order more mice and has to get this entire experiment done in 1 month. Hopefully, we will find a new STZ injection concentration and technique that will allot her the time to get this all done :P.

the end

I have finals right now, and everything is in the denoumont phase, which is fantastic because 3 out of 4 classes have graded me already with an A. All that's left is a cumulative clinical neurology exam :O. And it's my birthday tomorrow and my girlfriend is coming up, my dad wants to visit and I have an awards dinner for undergraduates in about an hour, I'm taking the MCAT in 20 days, applying to med school/getting rec letters... and a good friend is getting married and is having me in her wedding :P But I will get back to how my experiment is going, how we did STZ injections in mice and they all died, and how I'm starting the mating trials today. I will also get back to the hormone question posed by Ingrid, because it is a very good question :).

Memory

Cognition trials for the first 8 control rats was completed last night. It was amazing how quickly the rats learned where the platform was and how quickly they could orient themselves, and successfully navigate themselves to the platform. We did six learning trials, and once they got the hang of it, they found the platform within 15 seconds, no matter where they were placed in the pool to start. Some of them would crouch low on the platform and then jump at the pool rims in a clever attempt at escaping. None escaped, but not for a lack of effort. The pool rims are about 3 feet higher than the water level.

Between their learning trials, you put the rats in a 'comfort chamber', basically a cage full of paper towels where they can burrow, hide and dry off all at the same time.

In all, the experiment isn't as time consuming as I thought and it's kind of fun. To be honest, we were betting on the rats (silently, as to not interfere with the data) like it was the Kentucky Derby. My lucky number didn't turn out to be so lucky....