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Updated: Aug 1, 2026
Chronic Post-Ischemia Pain Model for Complex Regional Pain Syndrome Type-I in Rats
Published on: January 21, 2020
A Preterm Rat Model for Pain Studies
Ravena Carolina de Carvalho1, Ana Laura Silva1, Danielle Cavalcante de Paula1
1Laboratory of Neuroscience, Neuromodulation and Study of Pain (LANNED), UNIFAL-MG.
Insights
Neonatal pinprick stimulation in preterm rats did not alter baseline pain sensitivity but increased mechanical hypersensitivity in adulthood, particularly in females. This suggests long-term changes in pain processing due to early life stress.
Area of Science:
- Neuroscience
- Developmental Biology
- Pain Research
Background:
- Early life pain exposure, particularly in preterm infants, can have lasting neurodevelopmental consequences.
- Understanding the long-term effects of neonatal pain is crucial for developing effective interventions.
Purpose of the Study:
- To investigate the long-term impact of neonatal pinprick stimulation on pain sensitivity in adult preterm offspring.
- To establish a preterm rat model for studying early postnatal pain and its adult sequelae.
Main Methods:
- Neonatal rats born preterm underwent consistent pinprick stimulation.
- Adult rats were assessed for mechanical hypersensitivity using established pain tests.
- Complete Freund's adjuvant (CFA) was used to induce inflammatory pain.
Main Results:
- Neonatal stimulation did not affect baseline mechanical pain thresholds in adulthood.
- Adult rats exposed to neonatal stimulation showed increased mechanical hypersensitivity after CFA injection.
- Female rats exhibited heightened inflammatory hypersensitivity compared to males.
- Maternal behavior, litter weight, and offspring growth were unaffected.
Conclusions:
- Neonatal painful stimuli in preterm offspring can lead to altered nociceptive responses in adulthood.
- These changes may involve alterations in sensory processing and glucocorticoid receptor function.
- Further research is needed to elucidate mechanisms and develop interventions for adult consequences of neonatal pain.
Abstract:
This research delves into the consequences of consistent pinprick stimulation on preterm offspring to ascertain its long-term implications for pain sensitivity. The primary objective of this protocol was to investigate the impact of neonatal pinprick stimuli on the pain threshold in the later stages of life using a preterm rat model. By establishing this model, we aim to advance the research on understanding and managing early postnatal pain associated with prematurity. The findings of this study indicate that while the baseline thresholds to mechanical stimuli remained unaffected, there was a notable increase in mechanical hypersensitivity following complete Freund's adjuvant (CFA) injection in adult rats. Interestingly, compared with male rats, female rats demonstrated heightened inflammatory hypersensitivity. Notably, maternal behavior, the weight of the litters, and the growth trajectory of the offspring remained unchanged by the stimulation. The manifestation of altered nociceptive responses in adulthood after neonatal painful stimuli could be indicative of changes in sensory processing and the functioning of glucocorticoid receptors. However, further research is needed to understand the underlying mechanisms involved and to develop interventions for the consequences of prematurity and neonatal pain in adults.
