Rat and mice tissues do not have too much fat and are susceptible to dryness after processing specially when using xylene as "clearing" agent. I also think that your times are too long. The best processing protocol for rodent tissues is a sequence of 2-propanol → propanol+mineral oil → mineral oil → paraffin. It has produced great results in those labs that are using it. If you are interested I can send you under separate cover the procedure. René J.
________________________________ From: Katherine Murphy <katherine.o.mur...@gmail.com> To: histonet@lists.utsouthwestern.edu Sent: Thursday, August 2, 2012 11:07 AM Subject: [Histonet] Rodent processing and artifactual spaces Hello Histo Gurus, I have a question for you: I process rat and mouse tissues (kidney, liver, lung, brain, pancreas, GI, spleen) and have been seeing a separation artifact in the tissues (esp. kidney, brain, and heart) on the slides. I believe this is what was described as artifactual spaces between individual cells or cell shrinkage, as described by Carson (1997) under Fixation and Processing. The processing schedule that has produced this is: 50% Reagent Alcohol (RA), 70% RA, 80% RA, 95% RA x 2, 100% RA x 2, xylene x 2, and Paraplast Plus @ 60°C with vacuum, at 40 min per station for rat and 25 min per station for mouse. Preceding processing is a 20’ tap water rinse. Tissues have been in formalin for weeks in most cases but not always collected ideally (low formalin to tissue ratio, small jars used for large tissues, tissues submitted whole without slices or scores, etc)--we don't have much control over this part. Does anyone know what causes the separation artifact is and how it can be corrected? _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet