[Histonet] Rat heart valve histology trimming and sectioning reg

[JR R]

Assuming you are talking about the aortic valve....

Remove the heart and dissect away as much surrounding fat as you can.  Leave some aorta attached.

Make sure the heart is very well fixed in formalin.  If the heart is soft and floppy rather than firm the next step wont go well.

The next step is to remove most of the ventricles--you don't want to section through all that and it just gets in the way of proper orientation during embedding.

There are two ways to trim off the ventricle. The critical thing is that your sectioning plane is perpendicular to the angle at which the aorta exits the heart. 





The classic way is to lay the heart in the anatomical position and use a straight blade, like a razor, to cut through it, guillotine-fashion along a line drawn between the lower margins of the atria and which is perpendicular to the angle at which the aorta exits the heart.  I found that method to be not so reproducible so I came up with another way.

Under a dissecting scope, I use my right hand and fine forceps to suspend the heart by the stub of the aorta.  Gravity then automatically pulls the heart into almost the right position for the next step.  Next I use my left hand and a straight back forceps to grasp the heart just below the atria.  Then trim the aorta very close to the heart.  Use your fine forceps to twiddle the angle that the heart sits in the straight forceps until you are looking directly down into the aortic sinus.  You should be able to see the valves.  Now take a number eleven scalpel and in one or two smooth strokes, run it along the edge of the straight forceps, separating the ventricles from the top of the heart.

If you do it right you will have a sort of loaf shaped piece of tissue.  If you lay it flat under the scope, the stub of the aorta will be pointing straight up and you will be able to see the valves.  Embed the tissue so that the caudal side is at the bottom of the embedding mold.

Throw away sections until you start to see the valves.  Until you have cut a few and know what you are doing it is best to start saving sections early rather than later.  

I like to put three sections per slide and initially stain slides 1,3,4,7,9...etc, saving the rest for possible IHC.

My prefered stain for lesions is the Modified Movat Pentachrome.  It's kind of a pain to do but for lesion composition analysis it can't be beat.

I start lesion analysis at the point where I can see all the leaflets.  Stop when only the valve stems are visible.

Anyway, it will take you a while before you get reproducible, nice cross sections.  That first trimming away of the ventricles makes it or breaks it.

Good luck and feel free to ask clarifying questions.

Jerry Ricks
Research Scientist
University of Washington
Department of Pathology







> Date: Fri, 17 Sep 2010 08:39:40 +0000
> To: histonet <@t> lists.utsouthwestern.edu
> From: abijag76 <@t> rediffmail.com
> Subject: [Histonet] Rat heart valve histology trimming and sectioning reg
> 
> Dear Histonetters,
> 
> Our pathologists are interested in rat heart valvular lesions. I am working on trimming and sectioning methods to get uniform and reproducible morphology of heart valves in paraffin sections. It seems that available literature dealing with this is limited. Requesting your valuable experience in this regard.  
> 
> 
> 
> Thanks a lot
> 
> 
> 
> Abi jagannath
> _______________________________________________
> Histonet mailing list
> Histonet <@t> lists.utsouthwestern.edu
> http://lists.utsouthwestern.edu/mailman/listinfo/histonet