不同时间点减压对环扎法所致损伤脊髓Bcl-2、Bax蛋白的表达及意义

The expression and significance of Bcl-2，Ｂax following spinal cord injury induced by circle ligation after decompression at different time in rat

中文关键词:  脊髓损伤  环扎法  减压  凋亡  大鼠

英文关键词:Spinal cord injury  Circle ligation    Ｄecompression  Apoptosis  Ｒａｔ

中文摘要:

  【摘要】 目的：探讨不同时间点减压环扎法所致损伤脊髓中神经细胞凋亡及Bax、Bcl-2的表达及其意义。方法：成年SD大鼠84只，随机分为4组：A组，仅行椎板减压及硬脊膜囊周长测量；采用环扎法建立大鼠脊髓损伤模型，B组于环扎术后8ｈ行脊髓减压；C组于环扎术后72ｈ行脊髓减压；D组环扎术后不行脊髓减压。各组分别于术后1d、7d、14d、21d取材，所得脊髓标本行HE染色、Tunel染色及免疫组化法检测Bax、Bcl-2阳性细胞数等情况，并采用BBB评分评价大鼠后肢神经功能变化。结果：Bax染色：B组和C组术后1ｄ开始阳性细胞数增加，7ｄ时达高峰，14ｄ时仍较明显，21ｄ降低；D组术后阳性细胞数持续升高。Bcl-2染色：B组和C组术后阳性细胞数持续升高；D组术后１ｄ阳性细胞数最多，之后持续降低。Tunel染色：Ｂ、Ｃ及Ｄ组术后1ｄ开始出现凋亡细胞，7ｄ时达高峰，以后逐渐减少，21ｄ时仍可见。Bcl-2/Bax值与Tunel阳性细胞数关系：B组和C组二者存在负相关；D组二者呈正相关。BBB评分：A组术后1周后肢运动功能恢复正常；B组和C组术后逐渐升高（P<0.05）；D组术后1天开始逐渐降低，7天时最低，然后逐渐升高。组间比较结果需要补充，并标明P值（P＞0.05）。结论：环扎法可以建立稳定的大鼠脊髓损伤模型；早期减压能减少继发性脊髓损伤细胞凋亡，有利于神经功能恢复。

英文摘要:

  【Abstract】 Objective：To evaluate the neuron apoptosis and expression of Bcl-2 and Bax protein following spinal cord injury induced by circle ligation after decompression at different timepoint.Method：Eighty-four adult SD rats were divided randomly into four groups as following：group A，undergoing laminectomy and dural sac circumference measurements；group B undergoing decompression 8h later following ligation；group C undergoing decompression 72h later following ligation；group D undergoing ligation alone.Specimen of each group was harvested at 1 day，7　days，14 days and 21 days after surgery respectively.All specimenｓ were subjected to HE staining，Tunel staining and immunohistochemistry to evaluate the expression of Bax，Bcl-2 protein.The limb function was evaluated by using the BBB score.Result：Bax expression began to increase 1 day after decompression in group B and C，and reached peak at 7 days，while still remain visible 14 days after decompression，and then decreased at 21 days；group D increased gradually after surgery.Bcl-2 expression in group B and C increased continuously after decompression，while decreased continuously in group D.Under Tunel staining，apoptosis cells ｉｎ　ｇｒｏｕｐ　Ｂ，Ｃ　ａｎｄ　Ｄ　were evidenced 1 day after surgery，and reached peak 7 days later，then decreased，and still remained visible 21 days after surgery.Bcl-2/Bax ratio and number of Tunel positive cells showed negative association in group B and C，while positive in group D.BBB score in group A returned to normal 1 week after operation；while ｉｔ　increased continuously in group B and C；BBB score in group D decreased from 1 day after operation，and reached the lowest at 7 day，then increased gradully（P＞0.05）.Conclusion：Circle　ligation seems to establish the SCI model in rat，early decompression can decrease the secondary apoptosis and promote neurofunction recovery.