大鼠脊髓缺血再灌注损伤后caspase-12表达与细胞凋亡

目的:观察大鼠脊髓缺血再灌注损伤过程中细胞凋亡、caspase-12的表达变化规律,以探讨其分子机制。方法:采用自制压迫装置制备脊髓压迫缺血再灌注模型。运用形态学、分子生物学等方法,分别于缺血再灌注后3、7、11、23和47h,观察脊髓缺血再灌注损伤后,脊髓的病理变化和内质网的形态学改变、细胞凋亡及caspase-12的表达变化的规律。结果:脊髓缺血再灌注3h后,出现不同程度的细胞肿胀,神经元退行性变及内质网结构变化;随着再灌注时间的延长,神经元和神经胶质细胞凋亡数明显增加,并伴有caspase-12的表达增强;capspase-12表达与细胞凋亡的时空变化规律相一致。结论:在脊髓缺血再灌注过程中神经细胞凋亡是引起脊髓继发性损伤的主要病理因素,caspase-12可能参与了脊髓缺血再灌注损伤所导致的细胞凋亡。

Cellular apoptosis and caspase-12 expression following rat spinal cord ischemia/reperfusion injury

Objective: To observe the rules of cellular apoptotic change and caspase-12 expression in the rat spinal cord ischemia/reperfusion injury (SCII), so as to clarify the molecular mechanism of apoptosis after ischemia/reperfusion injury of the rat spinal cord. Methods: Fifty-six adult Wistar rats (250-300g) were randomly divided into 2 groups, the control group (n=6) and operation group (n=50). The SCII model was established with a self-made device in the operation group. The operation process in the control group was the same as the operation group except the ischemia/reperfusion of the spinal cord. The segments of ischemia/reperfusion spinal cord were properly taken at an interval of 3,7,11,23 and 47h after reperfusion (n=10 for each group). The ischemia/reperfusion segments of spinal cord were examined by HE, Nissl, TUNEL staining, immunohistochemistry (IHC) test, Western blot and image analysis. Results: HE and Nissl staining showed edema of neurons and gliocytes, vacuolation in some neurons and spongy degeneration in the white matter of the injured spinal cord after 3h of spinal cord ischemia/reperfusion. IHC test and Western blot showed that in whole spinal cord caspase-12 expression increased at 3h after SCII, and peaked at 11h, but appeared to decline after ischemia/reperfusion for 23h, and reduced significantly at 47h. The apoptosis of neuron and gliocyte were observed at each investigation time after ischemia/reperfusion. Conclusion: The apoptosis is an essential factor in spinal cord ischemia/reperfusion injury, which might be associated with the expression change of caspase-12.