不同压迫速率下羊颈脊髓的病理变化研究

Pathological Changes of Cervical Spinal Cord Caused by Different Compression Rates in Goat

目的：建立羊颈脊髓压迫动物实验模型,观察不同压迫速率下羊脊髓微血管情况和神经细胞凋亡规律,探讨脊髓损伤机制。方法：28只10~12个月山羊,质量25~30 kg,随机分为4个实验组（每组6只）,对照组（4只）。所有山羊在麻醉后均经第二、三颈椎间孔置入6Fr一次性无菌双腔导尿管,球囊部位于硬膜囊前侧,末端留置体外。实验组导管内注入总量相等的0.9%氯化钠液：A组,0.7 mL/d;B组,0.1 mL/d;C组,0.05 mL/d;D组,0.025 mL/d。对照组导管内不注入0.9%氯化钠液。随后,处死山羊,取受压迫脊髓段做病理检查;采用HE染色观察颈脊髓形态学变化,采用末端标记法（TUNEL）检测细胞凋亡,采用免疫组化法检测CD34的表达。结果：HE染色结果显示,从A组到D组,羊脊髓神经细胞损伤逐渐加重;TUNEL法检测结果显示,D组细胞凋亡细胞比例显著高于对照组（P〈0.05）;免疫组化法结果显示,B组CD34阳性表达率显著高于对照组及其他3个实验组（P〈0.05）。结论：压迫速率不同可以引起山羊脊髓不同的病理变化,缓慢而长期的压迫给颈脊髓造成的损伤最大;受压前期脊髓微血管增多,这可能是脊髓内源性保护机制之一。

Objective：To establish a goat model of cervical spinal cord compression,and to observe the microvessels and apoptosis of the nerve cells in spinal cord under different rates of compression.Methods：A total of 28 goats aged 10-12 months,with the weight of 25-30 kg,were randomly divided into control group（n=4）and 4 experimental groups（6 goats in each group）.Sterile disposable 6 Fr double-lumen catheters were placed between the second and third intervertebral foramen after anesthetization.Goats in experimental groups were injected with commensurable 0.9% sodium chloride solution at different compression rates：（Group A,0.7 mL/d;Group B,0.1 mL/d;Group C,0.05 mL/d;Group D,0.025 mL/d）.Coppressed spinal cord segments were isolated for pathological examination.HE staining method was used to observe the morphologic changes of the cervical spinal cord,and apoptosis was observed using the method of TUNEL.CD34 expression was analyzed by immunohistochemical method.Results：HE staining showed that the slower the compression rate was,the more serious the pathological changes of the spinal cord nerve cells were.TUNEL method showed that the apoptosis of Group D was more obvious than the control group（P〈0.05）.Immunohistochemical method showed that the positive expression rate of CD34in Group B was obviously higher than that in the control group and the other three experimental groups（P〈0.05）.Conclusions：Different degree of spinal cord pathological changes in goats can be caused by different compression rates.Slow and long-term compression causes more damage to cervical spinal cord.Increase of microvessels in spinal cord at the early stage of spinal cord compression may be one of protective mechanisms.