Totally agree with Jackie's observations and the proper way to perfuse
lungs. It  usually guarantees nice morphology and it is best for consistent
results and the eventual procedural write up.  I have perfused many a lung
in the "poor scientist" method with a syringe and have seen both good and
bad morphology. A steady and patient hand is needed. I believe your problem
with frozen lung is not the perfusion rate as much as it is the
infiltration of media into lung, which will melt and destroy it when it is
sectioned. If you do not have an Instrumedics CryoJane (I think that is
still what it is called) it becomes difficult.  You want to perfuse with a
fixative (if necessary, we do not always) then use a 15% sucrose solution
to perfuse followed by a 1:1 sucrose:OCT (or other appropriate frozen
embedding media). Again slow and steady, but the 1:1 solution will fill the
airways and make a more consistent cutting surface. Please do not hesitate
to call me, I had the same problem a few years back and I am very happy
with my results now.....hmmm few years back.....hmmm more like 11 now :-)
Also for question #2 morphology is usually better on paraffin embedded
tissues but now that we have that solved it is usually better for the
immuno procedures (antigen maintained in a more "pure" form) without added
fixatives and processing. I don't believe anything is closer to the natural
state than fresh frozen non-fixed tissue...but a lot depends on which
epitope you are looking for. And if you are going to be using an FITC or
500-530nm marker you may want to investigate other fixatives instead of
formalin.
anita
402-559-3239
1. How does one fix and embedd postnatal mouse lung tissue? Stress on
maintaining architecture of the alveoli. I have had problems in maintaing
architecture with frozen sections. Any suggestions are most welcome.


2. For immunoflorescence on mouse lung sections using paraffin sections.
Does
it
give better results as compared to frozen sections.