Pathological section, as a key tool for medical diagnosis, carries the responsibility of deep understanding of diseases. This intricate production process is not only a scientific art, but also a bridge for communication between doctors and patients. Each step is a rigorous and meticulous crystallization, from tissue resection to final preparation of slices, each link is full of medical ingenuity and challenges. This article aims to reveal each step of this mysterious process, in order to provide readers interested in medicine and pathology with a clear and comprehensive perspective.
1. Tissue fixation
The first step in pathological sectioning is tissue fixation. The fixation process is crucial for preserving tissue structure and cell morphology. The laboratory will use 10% neutral formalin to process the tissue removed during surgery. Small samples need to be soaked for 6-8 hours, while large samples require 24-48 hours. This process ensures that the organization maintains its original form and structure in subsequent processing.
2. Pathological sampling
After tissue fixation, pathologists need to conduct detailed examinations to determine the exact location of the lesion. This process not only requires a high level of professional knowledge, but also strict adherence to operating procedures to ensure the accuracy and representativeness of the materials taken. After the sampling is completed, the selected tissue pieces are placed in a dedicated embedding box for subsequent dehydration, transparency, and wax immersion treatment. The accurate execution of this step is crucial for ensuring the quality of the final slice and the accuracy of diagnosis.
3. Dehydration, Transparency, and Wax Immersion
Dehydration, transparency, and wax immersion are crucial processes in the production of pathological sections. During the dehydration stage, gradient alcohol is used to gradually replace the moisture in the tissue, which is crucial as it ensures that the tissue will not be damaged or deformed due to moisture during subsequent processing. Next, the organization is treated with xylene to achieve transparency, which is beneficial for better observation of the organizational structure. The final step of wax immersion is to completely immerse the tissue in paraffin, allowing it to harden and maintain its shape, providing a solid foundation for slice production. This comprehensive process not only ensures the integrity of the organization, but also provides ideal conditions for subsequent slicing and staining. The entire process takes about 15 hours.
4. Tissue embedding
Tissue embedding is a key step in the production of pathological sections, which involves placing dehydrated, transparent, and wax soaked tissue into melted paraffin. After solidification in paraffin, the tissue is firmly fixed, providing a solid foundation for slice preparation. This process not only protects the structure of the organization, but also ensures that the tissue can maintain its integrity and details during subsequent slicing and staining processes. By precisely controlling the temperature and solidification time of paraffin, the fine structure of the tissue can be preserved to the greatest extent possible.
5. Slicing preparation
Slicers play a crucial role in this step. Fix the prepared wax block on the slicer, and the technician needs to control it accurately. Cut it into thin slices with a thickness of only 2-5 microns. The cut slices are then placed in warm water at a set temperature of 45 ℃ for flattening. After flattening, gently remove the tissue from the water using a glass slide, and finally place the slices in a baking machine for fixation on the glass slide. This process is a key preparation step before staining.
6. Staining Sealing
The final step is staining and sealing. Firstly, HE staining is performed, and the slices need to be treated with xylene dewaxing and different concentrations of alcohol to remove residues. Then stain the nucleus and cytoplasm with hematoxylin and eosin. After staining, the slices were cleaned and made transparent using alcohol and xylene. Finally, the slices are sealed between neutral gum and cover glass, taking care to avoid the formation of bubbles.
Summary: The process of making pathological sections is a precise science that requires strict execution of every step. This is not only to ensure the quality of the slices, but also to ensure that doctors can make accurate diagnoses based on these slices. Although this process may seem tedious to outsiders, for the medical community, it is an important tool for exploring the unknown and saving lives.