We present a standard pipeline to obtain MATC tumors and present tumor dynamics and pathological information. This module will help researchers to understand tumor oncogenesis and facilitate drug discoveries. The MATC facilitates the collection of MATC samples in the whole tumor oncogenesis course, and each is a spontaneous mirror model, with the complete immune system and immune microenvironment.
MATC can be used to study the effects of specific gene functions on ATC, understand the mechanisms of thyroid tumor progression, and ultimately improve the prognosis of ATC patients. To begin, weigh tamoxifen and dissolve it in 15 milliliters of corn oil by ultrasound at a concentration of 20 milligrams per milliliter. Then store it in a brown container at four degrees Celsius.
At around eight weeks, weigh the mice with electronic scales and then administer tamoxifen intraperitoneally twice at an interval of one week. After preparing the dissection tools and mouse-tissue fixing solution, fill a clean 10 centimeter dish with about 10 milliliters of sterile PBS for temporary tissue storage, and for washing off the blood from the tissue surface. For thyroid extraction, place the euthanized mouse on the dissecting board.
After disinfecting the neck area, use sterile scissors and forceps. Make a small incision above the center of the clavicle and continue at midline up to the mouth. Locate the submandibular gland and remove it to expose the anatomical location of the thyroid, which is near the thyroid cartilage and trachea.
Once the thyroid gland is located, carefully dissected from the rest of the neck region using sterile scissors, and put it in the previously prepared dish containing sterile PBS. Remove the blood from the surface of the thyroid tissue, and with sterile scissors, carefully cut off the trachea. Then put the thyroid tissue on the sterile cloth and measure the size of the left and right lobes of the thyroid gland using Vernier calipers.
Using a sterile blade, divide the left and right lobes of the thyroid gland into two parts. Put one part into two milliliters of 4%paraformaldehyde solution for fixation and another into liquid nitrogen for preservation. For extracting the lung and liver, pinch just above the mouse's penis after disinfecting the the area.
Then make a small incision and cut along the midline of the abdomen to the subclavian bone. Expose the abdominal cavity. After locating the liver in the upper part of the abdomen, carefully remove it and place it into a new dish containing sterile PBS.
Grossly observe and count the metastasis in the lung and liver, followed by obtaining a picture. With a sterile blade, divide the lung and liver tissues into two parts. As demonstrated previously, fix one part and preserve the other part in liquid nitrogen.
The tumor growth curve was plotted to observe the dynamic alteration of the tumor size. The tumors grew slowly in the early stage, and became dramatically faster in the late stage. On the other hand, a survival curve was plotted based on recorded survival time.
The median survival of MATC was 130 days. In addition, approximately 92%lung metastasis was found in most MATC. In the HE staining of the primary tumors and metastatic lung tissues of MATC, the one month inducible tissues showed incomplete solidified features and the coexistence of follicular structures and malignant cells, whereas the thyroid follicular structures disappeared and the tumor solidified completely after a two month induction.
The primary tumor revealed that the tumor cells were morphologically diverse, with pleomorphic giant cells and spindle-shaped cells. Furthermore, the HE staining of metastatic lung tissues showed that the normal lung tissue was a reticular structure with clear alveolar structures and airspaces. Nevertheless, lung metastases showed a loss of normal reticular structure, air cavity thickening, and lung parenchyma.
Meanwhile, the immunohistochemical staining of MATC tumor with different antibodies showed highly proliferative tumor cells, lymphocyte infiltration, an extensive infiltration of myeloid cells, which was consistent with clinical samples. During dissection, the anatomical location of the thyroid gland needs to be correctly understood. The thyroid gland is placed near the thyroid cartilage and the trachea.
