The Cutting and Floating Method for Paraffin-embedded Tissue for Sectioning

Summary

Here, we present a protocol to improve paraffin sectioning. This method combines cutting and floating using a simple thermostatic chamber to avoid the transfer process required by the conventional method. As a result, the efficiency and the number of intact paraffin sections were greatly improved.

Abstract

Sectioning of the paraffin-embedded tissue is widely used in histology and pathology. However, it is tedious. To improve this method, several commercial companies have devised complex section transfer systems using fluid water. To simplify this technology, we created a simple method using homemade equipment that combines cutting and floating within a simple thermostatic chamber; therefore, the sections automatically enter the water bath on the water surface. The hippocampus from adult mouse brains, adult mouse kidneys, embryonic mouse brains, and adult zebrafish eyes were cut using both conventional paraffin sectioning and the presented method for comparison. Statistical analysis shows that our improved method saved time and produced higher quality sections. In addition, paraffin sectioning of a whole specimen in a short time is easy for junior operators.

Introduction

Morphological study is important in the biological research. Although new technology has allowed researchers to observe their targets directly from the whole tissue or organisms^1,2,3, cutting the specimen into thin sections, followed by staining, remains the primary method fornot only tissue morphology but also protein targeting directly in the tissue. Light microscopy uses three section types: paraffin, frozen, and semithin. Although cryosectioning is common for protecting tissue antigenicity, and the specimen preparation is simple, the retained tissue morphology is poor and....

Protocol

All methods described here have been approved by the Animal Care and Use Committee of Nanchang University.

1. Assemble the Equipment and Connect the Microtome

1. Design the parameter per the requirements (Supplementary Figure 1).
2. Submit the parameter to a local factory to manufacture the acrylic boards.
3. Assemble all parts in sequence: Use chloroform to combine 7 commercial acrylic boards into a tank with a section channel and water bath (Figure 1).
   CAUTION: Chloroform produces toxic substances when it meets light and oxygen. Asse....

Results

The improved method increased the number of intact paraffin sections. We tested this new method on adult mouse hippocampal tissue, adult mouse kidneys, embryonic mouse brains, and zebrafish eyes. Water was added to the tank, and the water temperature was maintained between 38.0 °C to 40.0 °C. After a serially preparing the tissue samples, they were sectioned and compared to conventional sectioning. The new method avoided section loss and increased the proportion of intact sections in the .......

Discussion

To improve paraffin section morphology and solve the problem of wasted time during conventional paraffin sectioning, we created an improved paraffin sectioning method that combines cutting and unfolding. This improved method relies on simple equipment that comprises a section channel, a water bath and a heater with a temperature detection switch. The section ribbon enters the water bath through the section channel and unfolds automatically while cutting. Therefore, this method improves paraffin sectioning quality and eff.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Incubator	Boekel Scientific	133000-2
Ethanol	Sinopharm Chemical Reagent Co.,Lid	64-17-5
Xylene	Sinopharm Chemical Reagent Co.,Lid	1330-20-7
Paraplast	Leica	39601006
Heated Paraffin Embedding Module	Leica
Commercial acrylic board
Trichloromethane	Sinopharm Chemical Reagent Co.,Lid	67-66-3
Tubular electric heating element(12 V 200 W)
Temperature controller(12 V 120 W)	Mingsuo	XH-W3002
Rotary microtome	Leica
Neutral silicone sealant			Link the water channel with the microtome knife holder
Voltage transformer	Dearll	S-250-12
Disposable blade	Accu-Edge	4689
Hematoxylin	Baso Diagnostics Inc.	BA-4025
Eosin	Baso Diagnostics Inc.	BA-4025
Microslide	Sail Brand	7105
Neutral balsam	Sinopharm Chemical Reagent Co.,Lid	10004160
Coverslip	Citoglas	10212424C
Microscope	Carl Zeiss
Hydrochloric acid	Xilong Chemical	7647-01-0
Water bath for paraffin sections	Leica
HistoCore Arcadia C - Cold Plate	Leica
paraffin repellent spray	Thermo Scientific	9990420