because i haave been trying with formaldehyde and formalin for 48 hrs to fix my mice testicles and and when i dehydrate my samples and embed them with paraffin it seems that when i slice them that the paraffin did not penetrate the tissues. an one final question i don't have toluene i am using xylene could that be the problem ?
Sassine,
I regularly work with testicular tissues and would recommend using Bouin's fixative. At time of viewing you see the difference. With formalin the basement membranes of the seminiferous tubules is pulled away with a shrunken appearance, whereas with Bouin's fixative the seminiferous tubules are not changed.
For penetration, I would guess that the tunica may prevent some penetration. I use much larger testicles, so only cut a small piece of tissue to place in the fixative. I would try cutting the testicle in half or removing a portion of the tunica for better penetration.
Good luck.
Hello Sassine. Just a reminder, formalin is a ~37% solution of formaldehyde in water. 4% PFA is roughly equivalent to 10% formalin, not 10% formaldehyde (which would not normally be used for fixing tissues other than, sometimes, brain)
Either 4% PFA or 10% formalin wil fix fine. Penetration of formalin will be about 1mm/hr initially, dropping to 0.3mm/h. 48 hours will be more than adequate.
Paraffin not penetrating is more likely due to steps in processing that are too short, and the testicular capsule contributes to this. Xylene is in fact more commonly used than toluene so this is not a problem. I suggest you section or bisect the testicles after fixation and prior to processing.
Sassine,
I regularly work with testicular tissues and would recommend using Bouin's fixative. At time of viewing you see the difference. With formalin the basement membranes of the seminiferous tubules is pulled away with a shrunken appearance, whereas with Bouin's fixative the seminiferous tubules are not changed.
For penetration, I would guess that the tunica may prevent some penetration. I use much larger testicles, so only cut a small piece of tissue to place in the fixative. I would try cutting the testicle in half or removing a portion of the tunica for better penetration.
Good luck.
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