Thursday, July 23, 2009

Islet isolation (:

Hi! I'm back for episode 2!


Isolation of pancreatic islets from mice



Retrieved from BBC (2008). Scientists make weight loss claim. Retrieved on 01st July 2009, from: http://news.bbc.co.uk/2/hi/health/7372495.stm


For this experiment you will need these few things:
White mice, Anaesthesia, Surgical Scissors, surgical wire, Forceps, Syringe, Needle, Tube, Collagenase solution.

When I first stepped into the animal room, a strong smell engulfed me. At first I thought it smelt nice (maybe because it was before lunch), but as I babysit the mice longer, they started to stink. The mice were stored in a styrofoam with holes as they were transported from a facility (which I shall not name).

A total of 4 mice were used in this experiment. The mice were making a lot of noise and they kept moving around! They almost had the strength to push open the styrofoam cover and even tried to escape.

My senior picked up the mouse by its tail, and tried to hold up its head by its ears in between her thumb and index fingers and held the tail using her last finger. Basically, the mouse was immobilized by a hand. The other hand was used to inject the anaesthetic into the mouse’s abdomen. This has to be done carefully. If injected wrongly, this may cause the mice to die earlier, which will be no good for the experiment.

As you guys know, mouse is very small. Therefore my mentor used a binocular microscope for easier visualization. To ensure that the mouse is really asleep, she will pinch its legs to check for reaction. No reaction would indicate the mouse is asleep. Next, she used a surgical scissors to cut open the abdomen, and exposed its contents.

Do you know that a mouse’s liver is really big? At first, I thought the liver was the lung! Below the liver is the pancreas. First, my mentor skillfully tied up the bile duct with the surgical wire. Tying up the bile duct before injecting collagenase into the mice ensures that collagenase will only be injected in the pancreas. If not, collagenase solution will flow into the stomach and intestine, therefore the pancreas will not swell up. Next, she carefully inserted a small tube which contains collagenase into the bile duct. Collagenase is used to digest the external cells. Once collagenase is pumped into the pancreas, the pancreas starts to swell up. I once thought that the pancreas is green in colour, but actually it is quite yellowish-transparent. Once the entire amount is injected in, the tube was carefully removed and pancreas was removed and placed in a tube containing collagenase. The tube was then placed in 37*C waterbath. After the removal of pancreas, the mouse would die a few minutes later.

However, my observation did not stop here. As my senior needed to collect blood for her experiment, I watched as she inserted the needle into the mouse’s really small heart and took the small little amount of blood. It was really weird, as during the procedure, the mouse would have reflex action, almost like the mouse is having hiccups.

Lastly, after we have gotten what we needed, the mice were covered in aluminium foil for disposal.

after putting pancreas in collagenase, you'll incubate at 37oC for 17-18 minutes. after that, you'll shake the cells, to ensure homogenicity and check that there is no remnants. next, we will pour the solution into a petri dish. using a binocular microscope, islet cells are handpicked.the cells will be transferred into a petri dish containing RPMI (Roswell Park Memorial Institute) media which is suitable for islet growth. the cells. the handpicking of islet cells are repeated onto subsequent petri dishes to remove all the epithelial cells.
Although I wouldn't have a chance to ever cut the mouse open, but this has been a great experience, though this isn't and will not be my first and my last.

Lim Jia Hui (JOEY)
0703605F

16 comments:

  1. hi joey..

    just out of curiosity, u said that the anaesthetic injection has to be done carefully, if not the mouse would die earlier than expected... err.. does it really make much difference..?

    heeeheee... thank u...
    nadiah
    tg02

    ReplyDelete
  2. omg thats fast. answer to your question. yes it makes a difference in my experiment as we have to collect the pancreas when the mice is alive. if the mouse is dead, i dont think the collagenase solution will flow into the pancreas and make it swollen. so yupps, it makes a difference! (:

    hopes this answers your question. (:

    LIM JIA HUI (JOEY)
    0703605F Group 1

    ReplyDelete
  3. Hello Jia Hui! (:

    I would like to know how does injecting anaesthesia into other parts of the mouse kills it faster?
    Also, what is the purpose of isolating mice's pancreatic islets in this experiment?
    (:

    Tan Siew Ming
    0702862D

    ReplyDelete
  4. hi joey,

    u said that after the injection, the pancreas was removed. how was it done? thanks!

    zi shuang :)

    ReplyDelete
  5. to siew ming,
    the purpose of isolating mice pancreatic islets in this experiment is so that i can treat the islet cells with chemicals. islet cells consists of many other cells, one of which is beta cells. as you should know, beta cells are cells that secrete insulin, therefore they play the main role in diabetes.

    we have to make sure that the anesthesia is injected into the abdomen area (preferably the intraperitoneal area). if injection is not done carefully, and the needle bursts a blood vessel, the mouse might die from internal bleeding. the main purpose of this experiment is to isolate the pancreas, I wouldn't want my needle to "poke" into the pancreas. yupps.
    hopes this answers your questions (:

    TO ZISHUANG
    as after the collagenase solution is injected, the pancreas is swollen, this makes it easier to see the pancreas. after that you just use the surgical scissors and cut off the pancreas from the rest of the organs (stomach, intestines). I can't find a video on this. Hope this clears your doubt. (:


    LIM JIA HUI (JOEY)
    0703605F
    tg01 GROUP 2

    ReplyDelete
  6. hii~

    just wondering, why is the pancreas removed and then placed in a tube containing collagenase, even though collagenase solution has already been injected into the pancreas to make it swell before removal?

    thanks~

    Ang Yu Hui Jacelyn
    0702632A

    ReplyDelete
  7. Oh.. Got it!
    Thanks!

    Siew Ming
    TG 01

    ReplyDelete
  8. hi jacelyn,
    the amount of collagenase injected in is very little, probably 1ml.
    (i find that this concept is similar to food, whereby when you chew your food, you are introducing enzymes into your food. this is similar to the injection of collagenase into the pancreas. when the food is down in the stomach, food is engulfed in acid, which will breakdown the food faster. this is similar to whereby i place the pancreas in collagenase solution. this allows digestion to be faster)

    hopes this long winded explanation clears your question. (:

    LIM JIA HUI (JOEY)
    tg01 group 1 0703605F

    ReplyDelete
  9. You said collagenase digest external cells. What do you meant by external cells? More specificially?

    How does the collagenase works? Its mode of action?

    Alvin

    ReplyDelete
  10. hi joe
    i would like to know what kind of anathesia do you use?

    -raymon

    ReplyDelete
  11. Hi Joey

    Just wondering if there is any explanation or any other reasons to explain why the pancreas still doesnt swell if the bile duct has been tied and a correct amount of collagenase has been adminstered correctly into the pancreas?

    With regards
    Jordan Wong Wei Jie
    0703992H Group 9
    TG02

    ReplyDelete
  12. Hi Joey:)

    i want to ask why is the blood collected from the heart? What is the purpose of collecting the blood from the heart?

    Cheers,
    Gwendolynn Tan
    0703953J grp9
    TG02

    ReplyDelete
  13. wow... -.- so many questions!

    to alvin,
    Collagenase is an enzyme,that cleave peptide bonds in collagen molecules. collagen is the most abundant protein in tissues,and they form the supporting tissue of connective tissues. so when you digest these tissues, you will obtain pancreatic islet cells. Hope this answers both of your question.

    to raymon, we use sodium pentobarbital (Nembutal). (:

    hi jordan, yes, you didn't "poke" (insert) the tube into the bile duct. actually, it is not easy to correctly insert the tube into the bile duct. it takes many times of practice to correctly insert the tube into the bile duct. you could try killing 12 mice, and never once got the tube into the bile duct.
    to clear the doubt, i notice my mentor didn't use a specific amount of collagenase to inject in. the purpose of collagenase at that step (injecting into the bile duct) is just to swell up the pancreas for easier removal.

    hope this answers your question!

    hi gwen,
    for the blood collecting from heart, it's my senior's project. firstly, you see the mouse is very small, its veins are very small, and has very little blood (like ml, unlike humans in litres!).so instead of finding a very small vein to take blood (worse still, it's not guaranteed you can get alot of blood), u can just get from the heart, where all the blood will flow pass. hope this answer your question.. (for your the other question, i'll answer you tomorrow!) (:

    hope this answers ALL your questions!! (:

    LIM JIA HUI (JOEY)
    group 2 tgo1
    0703605F

    ReplyDelete
  14. Jiahui (Joey),

    Your title for your post is isolation of pancreatic islet cells. However, so far you mentioned about how you prepare the pancreas or maybe calling it "surgically remove the pancreas".
    I want to know how you isolate these islet cells after you obtain the pancreas (putting the pancreas in collagenase - then?
    Or you meant the whole pancreatic cells are your islets?

    Li Yinliang Alex
    TG02 0704894E
    Group 8
    28 July 2009

    ReplyDelete
  15. to alex,


    after putting pancreas in collagenase, you'll incubate at 37oC for 17-18 minutes. after that, you'll shake the cells, to ensure homogenicity and check that there is no remnants. next, we will pour the solution into a petri dish. using a binocular microscope, islet cells are handpicked.the cells will be transferred into a petri dish containing RPMI (Roswell Park Memorial Institute) media which is suitable for islet growth. the cells. the handpicking of islet cells are repeated onto subsequent petri dishes to remove all the epithelial cells.

    hope this answers your questions

    LIM JIA HUI (JOEY)
    0703605F GROUP2 TG01

    ReplyDelete
  16. to gwen, reply to your 2nd question... i can't answer as it's confidentality. (the blood is used in experiment yupps.. ) (: do understand!! (:

    LIM JIA HUI JOEY
    0703605f TG01 GROUP 2

    ReplyDelete