Many laboratory researchers are accustomed to storing tissue wax blocks for a long time at room temperature after sectioning, and the tissue after sectioning is prone to antigen loss for long-term storage at room temperature.  Some studies have found that when sections are stored at room temperature for more than 3 months, immunohistochemical staining results are weakened or even negative. Therefore, some scholars have carried out new and old slice preservation time control experiments. 11 different tissue wax blocks were selected and 10 pieces were cut continuously for a total of 110 pieces per case, and placed in room temperature air for 1 month, 3 months, 6 months, and 1 year, and then the control experiment was carried out with new sections. The experimental results showed that when stored at room temperature for 3 months after wax sectioning, the sensitivity of antigens to most antibodies decreased by 50%, and the antigen loss of some sections was more. Most antibodies did not show positive results after 6 months of sectional storage, and only a few sections had weak positive expression after storage for more than 1 year, especially nuclear expression antigen loss was more prominent.  The reason may be related to oxidation, so in practical work, wax sealing sections and -20 degrees cryopreservation tissue sections can be used to avoid antigen loss, or paraffin tissue blocks can be stored at 4 degrees, and then sectioned when used, which can greatly reduce the antigen loss rate.

Frozen sectioning method is the most commonly used sectioning technique in histochemistry, especially enzyme histochemistry, fixed or unfixed tissue samples can be frozen section, fresh tissue frozen sections for tissue intracellular enzyme preservation is also a commonly used sectioning method in immunocytochemical research, can better preserve a variety of antigens, especially the antigenicity of surface antigens.  1. PreparationClean up the test bench and instrumentsTurn on the cryomicrotome and pre-reduce the cryomicrotome to the required temperature (-15~-20 °C)Prepare the processed slides, blades, glue and medicines  2. Clamp the frozen tissue block on the microtome holder, start the rough advance and withdrawal button, turn the knob, and smooth the tissue. 3. Adjust the thickness to be cut, according to different tissues, in principle, it is a cell-intensive thin cut, and the fiber multicellular thin can be slightly thick cut, generally between 5 ~ 10μm. 4. Adjust the anti-coil plate. The key to making frozen slices lies in the adjustment of the anti-roll plate, which requires the operator to be careful and accurately adjust it well and adjust it to the appropriate position. When slicing, cut out a complete, smooth slice. When the cut tissue adheres to a clean slide, gently apply a gentle force in one direction to avoid wrinkles during the tissue spreading process, ensure the integrity of the tissue structure and the beauty of the section.

To promote the spirit of scientists and stimulate the innovation vitality of the whole society, on May 24th, Vic science popularization volunteers entered the campus and prepared a unique science popularization activity for students. The content of this science popularization activity is rich and colorful. Through exhibitions, interactions, experiences, lectures, and other forms, we have brought a science popularization feast to children. In the coming time, our science popularization activity will have more exciting content waiting for everyone to explore. I hope everyone can gain full joy in this feast of knowledge and become little experts in life! I also wish the children a happy International Children's Day in advance!