胶原酶对大鼠急性坐骨神经痛模型体内磷脂酶A2活性的影响

目的 观察胶原酶对体内磷脂酶A2活性的影响。方法 42只Wistar大鼠随机分为3组：盐水治疗组、地塞米松治疗组、胶原酶治疗组。大鼠在各时间点（第0天造模前，第7天治疗前，第14天处死前）用vonFrey纤维测量双侧后肢机械刺激回缩阈值。第0天，每组随机抽取1只共3只大鼠处死，测量双侧坐骨神经节段磷脂酶A2活性为基线，其余39只大鼠右侧坐骨神经制作急性坐骨神经痛模型（Maves改良的Bennet-Xie模型），对侧行Sham手术；第7天，每组随机抽取3只处死，测量治疗前模型和Sham坐骨神经节段的磷脂酶A2的活性；第14天，剩余大鼠处死后测量各组模型和Sham坐骨神经节段的磷脂酶A2的活性。结果 所有大鼠在术后24～72h均出现炎症性单根神经病相关的行为学改变：包括步态紊乱、受累后肢的屈曲畸形和机械刺激痛觉过敏。术后7天时组间痛觉过敏的机械刺激强度类似。术后14天，机械刺激痛觉过敏在地塞米松和胶原酶组明显比生理盐水组低（P〈0．01）；磷脂酶A2活性在胶原酶组和地塞米松组明显低于生理盐水组（P〈0．01），地塞米松组和胶原酶组在机械刺激回缩阈值和磷脂酶A2活性均无显著性差异（P〉0．05）。结论 胶原酶在体内有抑制炎症反应特性，在炎症性坐骨神经痛活体模型中可以降低磷脂酶A2活性，改善机械刺激痛觉过敏症状。

Collagenase-induced reduction of phospholipase A2 activity in vivo rat model of acute sciatica

Objective To study the effect of collagenase on the phospholipase A2(PLA2) activity invivo animal models. Methods Forty-two Wistar rats were randomly divided into three treatment groups: 1)saline, 2) dexamethasone, 3) collagenase. The animals were tested for mechanical hyperalgesia with von Freyfiber on Day 0 (preoperation), Day 7 (pretreatment), and Day 14 (prior to death). Three animals randomlyselected from three groups (each animal from each group) were killed on Day 0 to determine the baseline ofPLA2 activity within unmanipulated rat sciatic nerve; other 39 animals underwent operation for model-makingof acute sciatic (Maves-modified Bennet-Xie model) on right sciatic nerves, while Sham operations wereperformed on left sciatic nerves. On Day 7, 3 animals from each group were killed to assay PLA2 activity priorto treatment. The remainders were given a single local injection of saline, dexamethasone or collagenase intothe inflamed sciatic nerve. On Day 14, the remaining animals were killed and their sciatic nerves wereharvested to assess PLA2 activity. Results All animals developed behaviour changes consistent withinflammatory mononeuropathy 24 to 72 hours postoperatively, including gait disturbance, flexion deformityand hyperalgesia of the involved hindlimb. The degree of mechanical hyperalgesia of the animals in diffirentgroups was comparable on Day 7. By Day 14, the mechanical hyperalgesia was less evident in the dexametha-sone- and collagenase-treated groups than in the saline-treated controls (P<0.01). The level of PLA2 activitywas lower in the dexamethasone- and collagenase-treated groups than in the saline-treated controls (P<0.01).There was no significant difference between the dexamethasone- and collagenase-treated groups (P>0.05).Conclusions Collagenase exhibits anti-inflammatory properties in vivo and may reduce PLA2 activity andameliorate mechanical hyperalgesia in this model of inflammatory sciatic neuropathy.