脊髓损伤后急性期甲基强的松龙干预对脊髓神经细胞凋亡的影响

Effect of methylprednisolone on the neurocyte apoptosis following acute spinal cord injury

中文关键词:  脊髓损伤  急性期  甲基强的松龙  细胞凋亡  TUNEL

英文关键词:Spinal ｃord ｉnjury  Acute stage  Methylprednisolone  Apoptosis  TUNEL

中文摘要:

  【摘要】 目的：观察脊髓损伤后即刻甲基强的松龙干预治疗对脊髓神经细胞凋亡的影响，探讨该药物促进脊髓神经功能修复的机制。方法：采用改良Allen′s法建立脊髓损伤（SCI）兔动物模型，实验动物随机分为假手术组（S组）36只，单纯损伤组（C组）与MP治疗组（T组）各36只，分别于损伤后8h、24h、72h、7d、14d和28d时随机取6只动物灌注固定取材，HE染色观察损伤区脊髓组织的病理改变，TUNEL法检测各组脊髓标本细胞凋亡情况；分别于损伤后1d、3d、7d、14d及28d观察各组动物运动神经功能情况，包括Rivlin斜板试验和BBB评分。结果：术后C组和T组斜板试验临界角度值和BBB评分值随时间点延长均逐渐升高，损伤7ｄ及之后各时间点，T组均高于C组，但小于S组（P<0.05）。HE染色S组脊髓组织在各时间点未见明显异常；T组及C组损伤后8h、24h及72h时脊髓组织结构紊乱，可见不同程度出血、神经细胞水肿、坏死，灰质中空泡形成，炎症细胞浸润，两组无明显区别；损伤后7ｄ、14ｄ及28ｄ，T组脊髓组织较Ｃ组恢复较好，整体损伤程度轻，血肿逐渐吸收，空泡减少，灰质和白质坏死吸收并胶原纤维组织增生，胶质细胞减少，可见较多神经细胞。TUNEL法检测凋亡细胞，S组未发现阳性细胞，C组及T组在损伤后8h可见阳性细胞，24h达到高峰，3d时仍较多，术后7d渐渐减少，14d及28d时阳性细胞数明显降低。两组对比，在损伤后8h、24h、3d及7d四个时间点，T组阳性细胞明显少于C组（P＜0.05），14d及28d时两组比较无统计学意义（P＞0.05）。结论：MP在脊髓损伤急性期干预治疗，有利于损伤的脊髓神经功能恢复，可能通过抗细胞凋亡机制产生作用。

英文摘要:

  【Abstract】 Objectives: To observe the effect of methylprednisolone on the spinal nerve cell apoptosis following acute spinal cord injury(ASCI) and investigate the mechanisms of spinal cord recovery. Methods: The spinal cord injury models were made according to Allen′s weight-drop method. All animals were divided randomly into 3 groups: sham group (group S, 36 rabbits), control group (group C, 36 rabbits) and treatment group (group T, 36 rabbits). Six rabbits were selected randomly and sacrificed, and the specimens were fixed with 4% paraformaldehyde at 8h, 24h, 72h, 7d, 14d and 28d after injury. Spinal cord motor nerve functions were evaluated by Rivlin loxotic plate scores and BBB Scoring system. The pathological changes among three groups were compared and analysed by HE staining and TUNEL test. Results：　The loxotic plate critical angles and BBB scores after injury gradually increased in group C and T but remained unchanged in group S. The angles and scores of group T were higher than group C but lower than group S at each time-point in the following 7 days (P<0.05). No obvious changes were noted for HE staining in group S at different time points, spinal cord tissue lost its normal structure. Varying degrees of edema and neurocytes necrosis, vacuoles formation in gray matter, neutrophils and bleeding were noted in necrotic area in both group C and T. There were no significant differences between two groups at 8, 24 and 72 hours following SCI. Group T had better neurofunction recovery than group C at 7, 14 and 28 days. And group T had better recovered than group C at 7, 14, 28 days following SCI which presented with light degree of injury, gradually resolved haematoma, decreasing vacuole and gliocyte, resolving of gray and white matter and increasing of collagen fiber and neuron. Apoptotic cells were found in group C and T at 8 hours, which reached peak within 24 hours, maintained high level at 3 days, and decreased slowly at 7 days after injury, and the number of cells significantly decreased at 14 days and 28 days by TUNEL test, but no such findings were noted in group S during the whole period. At 8 hours, 24 hours, 3 days and 7 days, there were less apoptotic cells in group T than in group C (P<0.05). But no significant difference was found between group C and T at 14 and 28 days (P>0.05). Conclusions: Early use of methylprednisolone in acute SCI contributes to neurofunction recovery, which may be by means of anti-apoptosis.