Orthotopic Inoculation of Ovarian Cancer Cells into Murine Ovary: A Procedure to Establish an Ovarian Cancer Mouse Model to Study Peritoneal Dissemination of Cells

Orthotopic inoculation helps deliver cancer cells to a recipient animal at a specific tissue or site matching the cells' natural anatomical location. To begin, prep an anesthetized female nude mouse, belly side down, on an operating stage. Make a vertical incision near its spine at a position between the rib cage and the femur. Open the abdominal muscles to expose the peritoneal cavity partially. Locate one of the ovaries.

Prepare a suspension of ovarian cancer cells with chilled extracellular matrix in a syringe. The low temperature prevents the suspension from solidifying. Inject this suspension into the mouse's ovary. Hold the needle in place to allow the matrix to solidify and embed the cancer cells within the ovary. Retract the needle. Suture the incision to close the wound. Allow the mouse to recover.

Over time, the injected ovarian cancer cells proliferate to form a primary tumor. Eventually, a few cells detach from their primary location and disseminate within the peritoneal cavity. When these migrating tumor cells attach to the peritoneal cavity lining, they invade the peritoneal tissue and proliferate to form metastasized secondary tumors.

To carry out orthotopic inoculation, after anesthetizing an eight-week-old female nude mouse according to the text protocol, perform a toe pinch to verify depth of the anesthesia. Place the anesthetized mouse on an operating stage, belly side down. Then, disinfect the surgical area with several washes using a chlorhexidine-based scrub and alcohol.

Next, make an approximately 2-centimeter vertical incision near the spine, between the right costal arch and the femur. Place a sterile surgical drape around the incision site. Then, fix the incised skin surfaces with clamps to maintain the opening.

Now, make a second 1-centimeter incision at the parietal peritoneum under the first incision to open the abdominal cavity. Then, clamp the incised abdominal surfaces. With a clamp, clip the fat tissue that surrounds the ipsilateral ovary and fallopian tube to remove the ovary from the abdominal cavity.

Then, carefully place the ovary and fallopian tube on gauze before placing the mouse, belly side down, under the dissecting microscope. Transfer the cell suspension to an insulin syringe. Then, immediately and carefully inject 1 to 2 microliters of the prepared cell suspension into the ovary.

For several seconds, keep the needle in the ovary to ensure that the hydrogel sets. After gelation, the injected tumor cells will remain in the ovary. Carefully, return the ovary into the body. With sterile medical silk, suture the second incision before using wound clips to seal the skin.

• Orthotopic Inoculation - Process of delivering cancer cells to a specific tissue in a recipient animal.
• Ovarian Cancer - A type of cancer that starts in the ovaries of female mammals.
• Ovarian Cancer Cells - Cancerous cells that originate in the ovaries.
• Murine Model - A lab mouse used for experimental purposes.
• Peritoneal Cancer - Cancer that develops in the lining of the abdomen called the peritoneum.

• Introduce Orthotopic Inoculation - Placement of cells in their natural location (e.g., ovary of mouse).
• Key Concepts - Understand the development of ovarian cancer (e.g., tumor inoculation).
• Underlying Mechanisms - Description of how cancer metastasizes (e.g., peritoneal dissemination).
• Connect to Experiment - Contextualize the murine model's role in studying ovarian cancer.

• What is orthotopic inoculation and how does it relate to ovarian cancer cells?
• Why are murine models crucial for understanding ovarian cancer?
• How does peritoneal dissemination contribute to metastasis?

• Describe Practical Applications - Orthotopic inoculation aids in studying cancer (e.g., ovarian tumor).
• Industry Impact - Research impacts oncology and healthcare (e.g., cancer treatment).
• Societal Importance - Advancements may increase survival rates (e.g., improved therapy).
• Link to Scientific Advancements - Discoveries entail new therapeutic technologies.