硬膜外腔植入异体髓核组织对大鼠痛阈的影响

Effect of nucleus pulposus allografted into epidural space on pain threshold in rats

目的:观察硬膜外腔注入异体髓核组织对大鼠痛阈的影响,以期为椎间盘源性疼痛提供理论依据。方法:实验于2005-06/08在首都医科大学宣武医院动物实验中心完成。选择SD雄性大鼠27只,随机分为3组,假手术组、脂肪组和髓核组,每组6只。另外9只雄性SD大鼠用来提供异体脂肪和髓核。假手术组硬膜外腔无植入腹膜外脂肪,脂肪组植入异体大鼠腹膜外脂肪(约10mg),髓核组硬膜外腔植入尾椎髓核(约3.0～4.0mg)。在术前、术后3,7,15,30d分别测定鼠尾对经皮电刺激(观察引起大鼠甩尾时的电流大小,即电刺激甩尾阈值)、温度刺激(观察自浸入至出现甩尾的间期,即温度刺激甩尾潜伏期)及机械刺激(观察引起甩尾时的砝码重量总和,即机械刺激甩尾阈值)的反应。结果:纳入动物18只,均进入结果分析。术后假手术组和脂肪组大鼠对经皮电刺激、温度刺激及机械刺激的痛阈与术前比较差异无显著性(P>0.05);而髓核组在硬膜外腔植入异体髓核后对经皮电刺激[以术后15d为例,假手术组、脂肪组、髓核组电刺激甩尾阈值变化百分比分别为1.08%,4.74%,-53.42%,P<0.05]、机械刺激[以术后15d为例,假手术组、脂肪组、髓核组机械刺激甩尾阈值变化百分比分别为2.10%,-1.21%,-43.77%,P<0.05]和温度刺激[以术后15d为例,假手术组、脂肪组、髓核组温度刺激甩尾阈值变化百分比分别为-4.12%,1.07%,-16.43%,P<0.05]均表现为痛觉过敏。结论:大鼠硬膜外腔注入异体髓核组织可造成大鼠痛觉过敏,这可能是椎间盘突出引起根性神经痛的原因之一。

AIM： To observe the effect of nucleus pulposus allografted into the epidural space on pain threshold in rats, so as to provide theoretical evidence for discogenic pain. METHODS： The experiment was carried out in the animal experimental center of Xuanwu Hospital, Capital University of Medical Sciences between June and August 2005. Twenty-seven male Sprague-Dawley rats were randomly divided into three groups with 6 rats in each： sham-operated group, fat grout and nucleus pulposus group. The allografted fat and nucleus pulposus were provided by the other 9 male SD rats. Rats in the sham-operated group were given an epidural space exposure without any graft implantation. In the fat group and nucleus pulposus group, rats had allografts of adipose tissue （approximately 10 mg） and nucleus pulposus （approximately 3.0-4.0 mg） implanted into epidural space, respectively. Preoperatively and at 3, 7, 15 and 30 days postoperatively, the responses of tail to transcutaneous electrostimulation （to observe the current caused by tail flick, which was the electrostimulated tail-flick threshold value）, thermal stimulation （to observe the duration from immersion to tail flick, which was the tail flick latency to thermal stimulation） and mechanical stimulation （to observe the total mass of counterpoises when tail flick, which was the tail flick threshold value to mechanical stimulation） were observed. RESULTS; All the 18 rats were involved in the analysis of results. The postoperative threshold values of rats to transcutanenous electrostimulation, thermal stimulation and and mechanical stimulation in the sham-operated group and fat group were not significantly different from the preoperative ones （P 〉 0.05）. In the nucleus pulposus group, there were electrical, mechanical and thermal hyperalgesias after nucleus pulposus allografted into the epidural space. At 15 days postoperatively, the changed percentages of tail flick to electrestimulation in the sham-operated group, fat group and nucleus pulposus group were 1.08%, 4.74% and -53.42%, respectively （P 〈 0.05）, those to mechanical stimulation were 2.10%,-1.21% and -43.77% respectively （P 〈 0.05）, and those to thermal stimulation were -4.12%, 1.07% and -16.43% respectively （P 〈 0.05）. CONCLUSION： Nucleus pulposus allografted into the epidural space can lead to the hyperalgesia of rats, which may be one of the reasons for radicular pain of a lumbar disc herniation results from nucleus pulposus.