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Updated: Aug 6, 2026
Preparation of Peripheral Nerve Stimulation Electrodes for Chronic Implantation in Rats
Published on: July 14, 2020
Prolonged Spinal Cord Stimulation Induces a Plateau in Carryover Effect: Evidence From a Neuropathic Pain Rat Model
Liwei Liu1, Zhichao Qiu2, Xin Zhao3
1Key Laboratory of Cellular Physiology, Ministry of Education; Shanxi Key Laboratory of Aging-related Diseases Mechanisms and Translation; and the Department of Physiology, Shanxi Medical University, Taiyuan, Shanxi, China; Department of Pain Management, First Hospital of Shanxi Medical University, Taiyuan, China.
Objectives:
The carryover effect of spinal cord stimulation (SCS), defined as persistent analgesia following the cessation of stimulation, is critical for chronic pain management. However, its relationship with stimulation duration remains unclear in preclinical models. This study investigated the impact of different SCS durations on carryover effect in a chronic constriction injury (CCI) rat model.
Materials And Methods:
To confirm the reliability of a paddle-electrode SCS model on the basis of clinical-grade equipment, we first performed validation experiments in CCI rats. We then examined the carryover effect and the dose-response relationship between different stimulation durations (4four hours, eight hours, 24 hours, and 72 hours). The carryover effect was evaluated through mechanical paw withdrawal threshold, thermal withdrawal latency (TWL), and open field test.
Results:
We successfully established a rat model of SCS using clinical-grade equipment and confirmed its reliability for investigating the carryover effect. All SCS groups across different durations exhibited significant suppression of mechanical allodynia during the stimulation period (p < 0.05). When the stimulation duration ≥eight hours, the carryover time (4.7 days) entered a plateau phase. In particular, a plateau (5.5∼6.3 days) was observed with ≥24-hour SCS, significantly longer than four-hour duration (1.5 days, p < 0.05). Furthermore, only ≥24-hour SCS significantly improved TWL on day one post stimulation (p < 0.05). No significant differences among groups were found in locomotor activity or anxiety-related behaviors.
Conclusions:
In this rat model, prolonged SCS enhances the carryover effect. A plateau in carryover time (4.7 days) emerges when the stimulation duration reaches ≥eight hours, and a further plateau (5.5∼6.3 days) is observed with ≥24-hour SCS, marking a critical threshold for sustained suppression of mechanical hypersensitivity and improvement of TWL.
