How to treat a brain tumor in rats? - briefly
Surgical removal of the lesion, combined with appropriate chemotherapy or localized radiation, constitutes the primary therapeutic approach, selected according to tumor histology and anatomical site. Adjunctive supportive care, such as analgesia and regular health monitoring, is required to maintain animal welfare.
How to treat a brain tumor in rats? - in detail
Effective management of intracranial neoplasms in laboratory rats requires a systematic approach that combines precise tumor induction, accurate assessment, and multimodal therapy.
Tumor induction is typically achieved through stereotactic implantation of tumor cells or genetically engineered constructs. Use a stereotaxic frame, drill a burr hole at predetermined coordinates, and inject 1–5 µL of cell suspension (10⁴–10⁵ cells) at a depth of 2–3 mm. Confirm placement with intra‑operative imaging or post‑mortem histology.
After tumor establishment (usually 7–14 days), evaluate lesion size and progression with magnetic resonance imaging or high‑resolution ultrasound. Quantify volume using the ellipsoid formula (π/6 × length × width × height) to guide therapeutic dosing.
Therapeutic modalities include:
- Surgical resection – Perform craniotomy under anesthesia, expose the tumor, and excise visible tissue with microsurgical instruments. Apply hemostatic agents and close the dura with sutures or tissue glue. Post‑operative analgesia (e.g., buprenorphine) and antibiotics reduce morbidity.
- Radiotherapy – Deliver focal irradiation using a small‑animal irradiator. Typical regimens: 2 Gy per fraction, 5 fractions per week, total dose 20–30 Gy. Shield non‑target tissues with lead blocks to limit collateral damage.
- Chemotherapy – Administer agents such as temozolomide (50 mg/kg oral gavage daily for 5 days) or carmustine (BCNU, 10 mg/kg intraperitoneally weekly). Adjust dose based on body weight and renal function. Combine with radiation for synergistic effect (concurrent chemoradiation).
- Targeted therapy – Use small‑molecule inhibitors (e.g., EGFR blockers, PI3K inhibitors) at doses established in pharmacokinetic studies. Verify target inhibition by Western blot or immunohistochemistry on tumor extracts.
- Immunotherapy – Introduce checkpoint inhibitors (anti‑PD‑1, anti‑CTLA‑4) via intraperitoneal injection (10 mg/kg) or adoptive transfer of activated T‑cells. Monitor immune cell infiltration with flow cytometry.
- Supportive care – Provide isotonic saline, nutritional supplements, and environmental enrichment. Monitor weight, grooming, and neurological signs daily. Euthanize according to humane endpoints if severe distress occurs.
Data collection should include survival curves (Kaplan‑Meier), tumor volume trajectories, and histopathological grading. Record adverse events such as weight loss >20 %, seizures, or infection.
Ethical compliance mandates Institutional Animal Care and Use Committee (IACUC) approval, justification of animal numbers, and implementation of the 3Rs (Replacement, Reduction, Refinement). Use analgesics, maintain aseptic technique, and limit invasive procedures to the minimum necessary for scientific validity.