Related Experiment Video
Updated: Feb 26, 2026
A Preterm Rat Model for Pain Studies
Published on: February 9, 2024
Early life vincristine exposure evokes mechanical pain hypersensitivity in the developing rat
Katie A Schappacher1,2, Lauren Styczynski1, Mark L Baccei1
1Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
Insights
High-dose vincristine (VNC) in young rats caused long-lasting mechanical pain sensitivity, impacting nerve fibers. This study establishes a model for chemotherapy-induced neuropathic pain in early life.
Area of Science:
- Neuroscience
- Developmental Biology
- Pharmacology
Background:
- Vincristine (VNC) is a key chemotherapy for pediatric cancers like acute lymphoblastic leukemia.
- Clinical data indicates VNC can cause peripheral neuropathy in children, but its lifelong impact on pain sensitivity is not well understood.
- A lack of early-life animal models for chemotherapy-induced neuropathic pain hinders research.
Purpose of the Study:
- To investigate the long-term effects of early-life vincristine (VNC) exposure on pain sensitivity in developing rats.
- To establish an animal model for studying chemotherapy-induced neuropathic pain originating in early life.
Main Methods:
- Rats were exposed to vincristine (VNC) at postnatal days 11-21.
- Mechanical and thermal pain sensitivity were assessed at various ages.
- Intraepidermal nerve fiber density was analyzed.
Main Results:
- High-dose VNC (60 μg/kg) induced mechanical hypersensitivity from adolescence into adulthood.
- This hypersensitivity included static and dynamic mechanical allodynia.
- Thermal pain sensitivity remained unaffected, suggesting a selective impact on mechanical pain.
- VNC treatment reduced intraepidermal nerve fiber density in hind paw skin.
Conclusions:
- Neonatal high-dose VNC exposure selectively causes persistent mechanical hypersensitivity.
- Aberrant sensory input during early development can lead to long-lasting pain processing alterations.
- This study provides a valuable model for investigating early-life chemotherapy-induced neuropathic pain.
Abstract:
Vincristine (VNC) is commonly used to treat pediatric cancers, including the most prevalent childhood malignancy, acute lymphoblastic leukemia. Although clinical evidence suggests that VNC causes peripheral neuropathy in children, the degree to which pediatric chemotherapeutic regimens influence pain sensitivity throughout life remains unclear, in part because of the lack of an established animal model of chemotherapy-induced neuropathic pain during early life. Therefore, this study investigated the effects of VNC exposure between postnatal days (P) 11 and 21 on mechanical and thermal pain sensitivity in the developing rat. Low doses of VNC (15 or 30 μg/kg) failed to alter nociceptive withdrawal reflexes at any age examined compared with vehicle-injected littermate controls. Meanwhile, high dose VNC (60 μg/kg) evoked mechanical hypersensitivity in both sexes beginning at P26 that persisted until adulthood and included both static and dynamic mechanical allodynia. Hind paw withdrawal latencies to noxious heat and cold were unaffected by high doses of VNC, suggesting a selective effect of neonatal VNC on mechanical pain sensitivity. Gross and fine motor function appeared normal after VNC treatment, although a small decrease in weight gain was observed. The VNC regimen also produced a significant decrease in intraepidermal nerve fiber density in the hind paw skin by P33. Overall, the present results demonstrate that high-dose administration of VNC during the early postnatal period selectively evokes a mechanical hypersensitivity that is slow to emerge during adolescence, providing further evidence that aberrant sensory input during early life can have prolonged consequences for pain processing.
