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目的 研究创伤性脑损伤后神经细胞凋亡聚二磷酸腺苷核糖多聚酶 (PARP)降解与DNA片段化的时序关系。方法 以大鼠落体撞击脑损伤为模型 ,分别于损伤后 2、6、12、2 4、4 8h处死取样。分别采用末端标记法 (TUNEL)测定DNA片段化 ,免疫组化法检测PARP降解。光镜下观察阳性细胞所在部位及形态 ,对等切片用HE染色作对照观察。结果 脑损伤后 2h开始出现PARP降解 ,6h开始出现DNA片段化 ,TUNEL阳性细胞最高密度均集中于损伤灶边缘部位 ,随时间推移 ,损伤灶深部区可见散在单个阳性细胞。其中PARP降解高峰出现在 12～ 2 4h ,凋亡细胞出现高峰在 2 4～ 4 8h。结论 创伤性脑损伤后存在细胞凋亡 ,且PARP降解高峰出现早于DNA片段化。建议在脑损伤早期使用抑制PARP降解的药物 ,可延缓细胞的凋亡
Objective To study the temporal relationship between the apoptosis of neuronal cells and the degradation of DNA fragmentation after traumatic brain injury. Methods The rats were impacted by traumatic brain injury and were sacrificed at 2, 6, 12, 2, 4 and 8 h after injury. DNA fragmentation was detected by TUNEL and PARP degradation by immunohistochemistry. Light microscope observation of the location of positive cells and morphology, and other sections with HE staining control observation. Results The degradation of PARP began 2h after brain injury, and DNA fragmentation began at 6h. The highest density of TUNEL-positive cells concentrated in the marginal part of the lesion. Single cells were scattered in the deep part of the lesion over time. Among them, the peak of PARP degradation appeared in 12 ~ 24 hours, and the peak of apoptotic cells occurred in 24 ~ 48 hours. Conclusion There is apoptosis after traumatic brain injury, and the peak of PARP degradation appears earlier than DNA fragmentation. Proposed early use of drugs that inhibit PARP degradation can delay cell apoptosis