臂丛全干不同损伤诱发神经病理性痛大鼠的痛行为学变化

摘要

Objective: To compare pain behaviors induced by ipsilateral avulsion and transection injuries of the whole brachial plexus in adult rats. Methods: Twelve adult female Sprague-Dawley rats were divided randomly into transection and avulsion groups, in which the transection and avulsion injuries of the right brachial plexus were respectively performed. Mechanical withdrawal threshold (MWT), cold allodynia scores (CAS) and thermal withdrawal latency (TWL) of the ipsilateral and contralateral hindpaws were evaluated before surgery and on the 3 rd, 7 th, 14 th and 28 th day after surgery. Results: No significant differences in the three pain behavioral indices were detected before the surgery between the bilateral hindpaws within the same group or between the two groups. CAS increased markedly (P < 0.01) while bilateral MWT and bilateral TWL remained unchanged in transection group as compared to those before the surgery. MWT was significantly declined (P < 0.01) and CAS elevated (P < 0.01) at all postoperative time points but no changes in TWL were found in avulsion group. Significantly, decreased bilateral MWT (P < 0.01), markedly increase CAS (P < 0.05), and similar bilateral TWL were detected at all postoperative time points in avulsion group when compared with transaction group. However, no differences in all three indices could be observed between the bilateral hindpaws or between different postoperative time points in the same group. Conclusion: Ipsilateral brachial plexus transection induced bilateral cold allodynia of hindpaws while the avulsion injury of the ipsilateral brachial plexus led to bilateral mechanical allodynia, and severe cold allodynia which maintained for at least 28 days as well. Therefore, avulsion injury of the whole brachial plexus, in comparison with transaction, may be a better animal model for the study of neuropathic pain.%目的:比较大鼠单侧臂丛全干切断伤与根性撕脱伤诱发神经病理性痛大鼠双侧后足的痛行为学特征.方法:将12只成年雌性Sprague-Dawley (SD)大鼠随机分为全干切断伤和根性撕脱伤两组,以右侧为手术侧,术前及术后第3d、7d、14d和第28 d检测大鼠双侧后足的机械触刺激诱发痛缩足闽值、冷刺激诱发痛评分及热刺激缩足潜伏期.结果:术前3项痛行为学指标在同一组动物双侧后足间和两组大鼠间无显著差异.与术前相比,切断伤组双侧冷刺激诱发痛评分明显增高(P＜0.01),机械痛缩足阈值及热刺激缩足潜伏期则无明显变化；撕脱伤组术后各时间点双后足机械痛缩足阈值显著降低(P＜ 0.01),冷刺激诱发痛评分显著增高(P＜0.01),而热刺激缩足潜伏期则无明显变化.与切断伤组相比,撕脱伤组术后各时间点双侧后足机械痛缩足阈值均显著降低(P＜0.01),双侧令刺激诱发痛评分则显著增高(P＜0.05),而热刺激缩足潜伏期则无显著差异.同组大鼠3项检测指标在术侧和健侧后足之间以及术后不同时间点之间无显著差异.结论:单侧臂丛全干切断伤仅诱发双侧后足冷刺激诱发痛,而全干根性撕脱伤不但诱发更为严重的冷刺激诱发痛,还导致双侧后足明显的机械触刺激诱发痛,这种痛行为学的变化可持续至第28d.因此,臂丛全干根性撕脱伤较切断伤更适合作为臂丛全干损伤诱发神经病理性痛的动物模型.