脊神经结扎后慢性病理痛大鼠异位放电的特点分析

CHARACTERISTICS AND CHANGES OF ECTOPIC DISCHARGES FROM INJURED FIBERS FOLLOWING SPINAL NERVE LIGATION

摘要:

目的:研究L5脊神经结扎模型大鼠的L5背根异位放电的特点及其时程变化.方法:以L5脊神经结扎制备大鼠神经病理性痛模型,利用分离背根单纤维细胞外电生理记录异位放电.结果:(1)记录到三类典型的异位放电,即紧张型、簇状及不规律型放电;(2)放电频率随着时间的推移而发生变化,术后24 h达峰值随后逐渐降低;(3)不同类型的异位放电所占比例也随时间而改变,20 h内以紧张型及簇状放电为主,后期则以不规律型放电占绝对多数,术后14 d只记录到不规律型放电;(4)记录到一类高频呈周期性的放电,此类放电很罕见,且仅出现在术后3 d之内.结论:脊神经结扎后,其对应的神经纤维产生大量的不同类型的异位放电,这种放电可能在慢性神经病理性痛的发生发展的早期起着重要作用.

Abstract:

Objective: Neuropathic pain rapidly occurs following spinal nerve ligation. The present study aims to investigate the characteristics and changes of ectopic discharges from injured nerve fibers after spinal nerve ligation. Methods: Using L5 spinal nerve ligation as neuropathic pain model of rats, teased fiber recording technique was used to explore the property of ectopic discharges. Results: (1) Three different firing patterns of ectopic discharges (tonic or regular, bursting, irregular) emerged after spinal nerve ligation, the proportions of which changed dramatically; (2) The frequency of ectopic discharges also changed rapidly in the present observation, reaching peak within 24h with gradual decrease in the following days; (3) Proportions of three different firing patterns changed dynamically over time. The tonic and bursting types were dominant in the first 24h, while the irregular became the only pattern at day 14; (4) One kind of special discharges with high frequency developed following spinal nerve ligation, which is characterized by occurring rarely and periodically in the first three days. Conclusion: The ectopic discharges from injured nerve fibers rapidly emerged following spinal nerve ligation. These discharges might be an essential mechanism underlying neuropathic pain.