The above comments are correct. 5 is standard, 7 for immune sometimes. THe iced water is a good tip, we lay our blocks on an ice block for 5-10 minutes before sectioning. If you are just looking looking at morphology with a routine stain and want a challenge try sectioning paraffin blocks at 2 or 3um, a bit tricky but the resulting sections/resolution will amaze you

Hello Milad, I guess you are sectioning paraffin embedded material. I try and section at 5 um although 7um would be more typical. Face your blocks and soak them in ice water, dry and section immediately for the best results. Be sure to decalcify your gill tissue if you are using a teleost fish. It will make your life a lot easier.

Good luck

Jonathan

Mr Esmailbegi

It is actually depends on your purpose. For paraffin embedded blocks 1-10um are recommended. We usually use 5um cutting for H&E staining. But if you use Resin blocks for TEM investigation your cutting would be less than 1um with glass blades.

Regards

The above comments are correct. 5 is standard, 7 for immune sometimes. THe iced water is a good tip, we lay our blocks on an ice block for 5-10 minutes before sectioning. If you are just looking looking at morphology with a routine stain and want a challenge try sectioning paraffin blocks at 2 or 3um, a bit tricky but the resulting sections/resolution will amaze you

Also keep in mind there are different types of paraffin that have different melting points making some "harder" than others.  There is a balance between MP and ability of the molten wax to penetrate different tissues.  If you have plenty of tissue available, I'd experiment with different MP paraffin formulations.  

I agree with all above answer, if you use ice water and it is still hard you can use soft block reagent

با سلام

4-7 micron

in the lot of papers, the best thickness for gill and liver of fish is 3-5 micrometer ,respectively.

In fishes I have the best morphology of gills and liver at 4 micrometers.

Hi Milad,

I agrre with all above answer. I want to add that if you are a beginner, you should better start at thicker sections (about 7-10 µm) and gradually shift to thinner sections till reach 3-4 which is preffered for traditional stainings for light microscope. thicker sections will give you better images for low magnification and thinner sections for higher magnification for detailed cell analysis.

Good luck

Hello Mr Esmailbegi

I understand you are sectioning paraffin embedded material. For paraffin embedded blocks 5-7um are recommended. I usually use 5-6um cutting for H&E staining and mucosubstans demostration.

   Good luck

According to my practice I cut paraffin blocks 6 micron and methacrylate(plastic) blocks at 3 micron

This is very much dependent upon what you want to see, the material you have embedded (and in what), and the stain you plan on using.  In standard paraffin (e.g. Paraplast (m.p. 56 degrees) standard practice allows cutting from 5-7 microns (of course standard compound microscope resolution rarely dips below 1 um so vertical depth resolution must be considered).  Moving to plastic will allow thinner sections.  Perhaps most importantly in your question is tissue type; liver fixes readily and usually cuts easily and at thinner sections.  The gill arches found in fish gills with proper fixation should also cause few problems when cutting but the tougher (harder) structure could produce the need for slightly thicker sections OR a move to plastic embedding.