[Histonet] injection marker for the spinal cord

[Caroline Bass]

Hello,

I am working on an experiment where I will inject the spinal cord of 
rats.  Is there a way to mark the injection site with a dye?  Basically 
I want to do my injection, wait several weeks and collect the tissue.  
So the dye would have to last a while.

Any suggestions would be appreciated.  I am particularly interested in 
the best way to process the tissues for the recommended dye.

Thanks,

Caroline Bass