When you speak about "shredded sections" a dull knife comes to my mind, maybe with nicks. Do you work with disposable blades? Do you change the knife often enough?

Ice water is about 0°C. It would be better to cool the block about -5 to -10°C.

How thick are your sections? 3-5 µm would be ok for paraffinslides.

The clearance angel may be too big. Clearance is the angel between surface and knife. Cutting angel is the slope of the knife. Do you speak about clearance or cutting angel?

Too big --> knifes hopps over the surface of the block. Too small --> compressed sections, only each second section comes off.

Hello Aman Az.

In our lab we give a deep breath (hot) to the block just before cut it when the tissue has a lot of blood (heart, spleen, liver). Then, we take the sections made to a pool of warm water (40ºC max) to stretch the sections.

I hope this steps can help you.

Try to avoid air bubbles around tissue, make well trimming, and adjust the knife angle

When you speak about "shredded sections" a dull knife comes to my mind, maybe with nicks. Do you work with disposable blades? Do you change the knife often enough?

Ice water is about 0°C. It would be better to cool the block about -5 to -10°C.

How thick are your sections? 3-5 µm would be ok for paraffinslides.

The clearance angel may be too big. Clearance is the angel between surface and knife. Cutting angel is the slope of the knife. Do you speak about clearance or cutting angel?

Too big --> knifes hopps over the surface of the block. Too small --> compressed sections, only each second section comes off.

Vicente's advice to float the sections on warm water to make them expand to their previous size (decompression) is sound. However, it seems that the problem is due to some property of the tissue and the paraffin embedding. In general, it is a good idea to limit exposure of tissue to xylene as this can make tissue brittle. Another possible solution is to double-embed, which strengthens the tissue. This means immersing the tissue in celloidin before proceeding to paraffin embedding. This does need some care, though, as the celloidin can harden and make the block difficult to cut.

Thanks everyone..

I tried all the suggested  solutions  with no luck, I am still getting a shredded sections:(

Since I am using  a Low-Profile Disposable Microtome Blades / Triple Facet , the suggested clearance angel is 8-10.

Any thought of changing the  clearance angel or changing the blade type???

Are the Skin Liver and Spleen samples  in the same block?

Hi Evelyn Lupton,

Different blocks.

Thanks

Dear Aman Az, section thickness plays a critical role. If you need to cut 4µm sections for normal histochemical analysis, you need to dry sections at 45-60ºC for 6h-O/N. In our Lab we dehydrate the sample to 100% ethanol and then infiltrate the tissue with xylene and later molten paraffin at 60-70ºC. We use a cutting angle of 15ºC because, in our experience,  more acute angle may not cut at all and larger angles may break off the section. If you use sections thicker than 25um, you must never allow baking temperature go higher than 50 ºC. Otherwise sections may crack.

How experienced are you with cutting? To check the cutting-system it may help to make a pure paraffin-block without tissue. This cooled block should lead to even and uniform sections without compressions and wrinkles. When you reach this by adjusting the angel and section thickness, you can try again the tissue-block. If the problems still remain, I would look for the issue in tissue-processing. Then you have to post your protocol here to get a sufficient answer.

In our lab, the tissue was crushed, it would have been for 1 hour in a solution of soap and water. This approach helped to soften the tissues.

Although the main cause of this type of drying can be caused by not properly processed tissues.

I propose to reduce the duration and  low percent of (0.8%) fixation.

Thanks so much everyone, truly appreciate all the responses.

Best,

Aman

When I have blocks that are difficult to section I use this trick:

Cut the block until you get where you want to start saving sections. 

Place the cut block in 5% Ultra Downy/water solution warmed to about 44 C for about 30 seconds. Rinse block with water. Cool in a freezer for about 5 minutes. Re-position the block on the microtome and section as usual.  I float my sections in 50% ethanol before transferring to a 44 C water bath to decompress. 

In our lab we found these reasons for "crushed" sections, so far:

1.) Wrong tissue processing; 2 serial alcohols were not 80% and 90% respectively, but lower values.All other chemicals were OK. SOLUTION: Since then we measure the density of each alcohol in the tissue processor before each run.

2.) Wrong paraffin; for unknown reasons there are some bad series of paraffin. Also some plastinated paraffins are UNCOMPATIBLE with some blade types and angles (try & experiment). SOLUTION: buy reliable paraffin and do NOT change blade types and angle when one combination works OK.

3.) Clean blade after some cuts, regularly! Tissue blocks must be cooled at least on -9 Celsius or lower. Ice water is NOT ENOUGH cool.- use cooling plate. An experienced tissue cutter, will get subjective experience in cutting after about 6 months of continuous work, This can not be learned by theory. Each tissue type MUST be cutted under different temperature conditions. Some cooler, the others "warmer".  (try & experiment).

4.) Wrong blate type, too hard or too soft. SOLUTION: change blade type to other hardness value.

5.) When you have micro folds on the ended/covered specimen, then there was an error in streching procedure. The water bath (after cutting) must be set at about 52 Celsius, 40 Celsius is often not enough! But it depends on paraffin type.

6.) The fixating  time is important. We use about 3-5 days period to fix tissue in 10% buffered formaline in max. cca. 1x1x1 cm tissue blocks. Thickness is significant. Do not under or overfixate tissue, it will be too hard or too soft for cutting. But you can prolong the fixation time for softer tissues, say liver, or spleen. In the prosessing session, use the whole series of alcohol (70%,80%,90%,100%) - if some is missing it could produce bad cutting effects also.