An Orthotopic Sciatic Nerve Xenograft for Neurofibromatosis Type 1 Neurofibromas
October 10th, 2025
Neurofibromatosis type 1 (NF1) leads to benign peripheral nerve sheath tumors (neurofibromas) that require a specific nerve microenvironment for growth. An optimized orthotopic xenograft model was developed, using intraneural injection of human Schwann cells into NSG mice. This model recapitulates human neurofibromas and provides a valuable platform to evaluate therapeutic strategies.
This research focuses on neurofibromas, a type of benign nerve sheath tumor to develop a preclinical model suitable for pharmacological studies. The challenge of this model was to establish an orthotopic intradural graft of human immortalized cells. Only one treatment is currently approved for neurofibroma.
While this represents a significant advance, there are still limitations, including toxicity and the development of resistance. The preclinical model will enable the screening of new compounds. To begin, place the anesthetized and analgesia-treated mouse on its right side and gently spread its hind legs apart.
Use povidone iodine to prepare a sterile surgical field and cover the surgical area with a sterile drape before making the incision. Then, make a five-millimeter skin incision parallel to the femur using fine scissors. Use fine forceps and micro scissors to gently separate the underlying muscle layers while avoiding damage to blood vessels.
Identify the sciatic nerve as a white, cord-like structure located medial to the femur. Next, take the cell suspension to be injected in a 1.5 milliliter tube and gently flick the tube to resuspend any settled cells. Load four microliters of the suspension into a 10-microliter Hamilton syringe fitted with a 33-gauge needle.
Now, insert the needle parallel to the sciatic nerve axis to a depth of approximately two millimeters. Slowly start injecting to create pressure and a gap between the nerve and the peripheral sheath, and advance the needle for approximately four to five millimeters. Then, slowly inject the suspension while withdrawing the needle from the nerve.
Perform the injection without stretching the sciatic nerve, and do not use clamps. Wait for 10 to 15 seconds before slowly withdrawing the needle to minimize reflux. Ensure that the sciatic nerve appears slightly swollen at the injection site with no leakage or discoloration.
A stable nerve appearance without extravasation confirms a successful injection. Finally, close the surgical incision using three to four simple interrupted sutures with non-absorbable material to avoid inflammation. If the surgery lasts longer than 10 minutes, administer one milliliter of Ringer's lactate subcutaneously.
Bioluminescence imaging showed localized signal at the sciatic nerve as early as day five post-injection, indicating successful tumor engraftment with exponential signal increase by day 33, reflecting progressive tumor growth. Dissection of the sciatic nerve at day 33 revealed a clearly visible, well-integrated tumor mass without signs of abscess formation, consistent with the bioluminescence imaging. Hematoxylin and eosin staining confirmed the presence of tumor tissue within the sciatic nerve, showing dense cellularity and focal invasion in all three representative samples.
Overview
This study develops a preclinical model for neurofibromas, benign tumors associated with neurofibromatosis type 1. The model utilizes intraneural injection of human Schwann cells into NSG mice, allowing for the evaluation of therapeutic strategies.
Key Study Components
Area of Science
- Neuroscience
- Oncology
- Pharmacology
Background
- Neurofibromatosis type 1 (NF1) is characterized by benign peripheral nerve sheath tumors.
- Current treatment options are limited and often associated with toxicity and resistance.
- There is a need for effective preclinical models to test new therapeutic compounds.
- This study addresses the challenge of creating an orthotopic intradural graft of human cells.
Purpose of Study
- To establish a reliable preclinical model for studying neurofibromas.
- To facilitate the screening of new pharmacological treatments.
- To better understand the tumor microenvironment necessary for neurofibroma growth.
Methods Used
- Intraneural injection of human Schwann cells into the sciatic nerve of NSG mice.
- Preparation of a sterile surgical field and careful dissection to avoid blood vessel damage.
- Monitoring tumor growth using bioluminescence imaging.
- Histological analysis with hematoxylin and eosin staining to confirm tumor presence.
Main Results
- Successful engraftment of tumors was confirmed by bioluminescence imaging.
- Visible tumor mass was observed at the sciatic nerve by day 33.
- Histological analysis showed dense cellularity and focal invasion of tumor tissue.
- The model provides a platform for evaluating new therapeutic strategies.
Conclusions
- The developed model effectively mimics human neurofibromas.
- This model can be utilized for screening new compounds and understanding tumor biology.
- Further research is needed to explore potential treatments for neurofibromas.
