08 August 2016 1 389 Report

I know this type of assay is better done with a rat however our circumstances left us using a mouse model. That being said, its pretty difficult to get this aortic ring to respond to much of anything. 

Our setup:

  • we are using powerlab by AD instruments with a 25mg-2 gram force transducer 
  • we are using a 25mL Radnoti tissue bath system
  • We have created hooks using tungsten wire with a diameter of .1mm that we thread through the lumen of the 3-4 mm aortic sections
  • These hooks are attached to sutures which loop around a glass hook on the bottom of the tissue bath and a force transducer at the top. 
  • We are using balbC mice

    • Our procedure:

  • Euthanize the mice
  • Extract the aorta (fasica included) and place it into ice cold Krebs Ringer Buffer
  • Thread the tungsten through the aorta (in the past we used to strip off the fascia, however we were concerned that we may be damaging the aortic smooth muscle, so until we can rule that out, we have been leaving the fascia on).
  • attach the suture / tungsten wire /aortic ring to the glass tissue bath clamp and the force transducer
  • we incubate it in the tissue bath at 37 degrees Celsius and change out the KRB every 15 minutes.
  • we typically let it sit under no tension for 30 minutes, then at that point adjust the passive tension to about 800mg.
  • Then we administer a supraphysiological concentration of L-phenylephrine and....nothing.

    • Our responses thus far have been pretty much nonexistent. Any advice or tips would be appreciated. I am attaching an image of a recent test where we think we got some sort of response, just not anywhere near where we thought we would be (for instance the highest change in tension in this experiment was ~ 70mg whereas we've read people have as high as 400mg).

    Thanks!

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