新生鼠缺氧缺血性脑损伤S-100 NSE mRNA和蛋白水平变化

Changes of the Expression of the mRNA and Protein Level of S-100 and NSE after Hypoxic-ischemic Brain Damage in Newborn Rats

摘要:

目的 研究缺氧缺血性脑损伤(HIBD)后血和脑脊液中S-100蛋白(S-100)、神经元特异性烯醇化酶(NSE)水平的变化及其与脑细胞死亡数的相关性，并探讨这些蛋白质水平变化的机制。方法 采用7 d龄SD大鼠HIBD模型，应用放射免疫方法动态观察HIBD血液和脑脊液中S-100，NSE水平的变化，用RT-PCR的技术和免疫组织化学的方法动态观察HIBD后不同时间点脑组织中S-100，NSE mRNA和蛋白水平表达的变化。结果 HI后血液中24 h，48 h S-100分别为(1.205±0.183) μg/L和(1.235±0.097) μg/L，NSE分别为(3.97±0.228) ηg/ml和(3.76±0.234) ηg/ml，对照组S-100和NSE分别为(0.645±0.05) μg/L和(3.15±0.164) ηg/ml。脑脊液中24 h，48 h S-100分别为(1.28±0.031) μg/L，(1.32±0.097) μg/L，NSE分别为(7.15±0.717) ηg/ml，(4.29±0.144) ηg/ml，对照组S-100和NSE分别为(0.68±0.059) μg/L和(3.42±0.322) ηg/ml。血液和脑脊液中S-100，NSE在24～48 h与各自对照组比较都有明显增加(P<0.01)，同时其水平的变化和脑细胞死亡数呈正相关。NSE mRNA转录高峰出现在缺氧缺血后24 h，而S-100 mRNA高峰在48 h。HIBD后不同时间点脑组织S-100蛋白的表达阳性面积的变化是随时间变化逐渐增加(12～96 h)。NSE表达的阳性面积随HIBD时间延长呈进行性减少(P<0.01)。结论 S-100，NSE能作为缺氧缺血性脑损伤的标志物，在缺氧缺血后24～48 h为取标本合适时间。血液和脑脊液中S-100水平的升高，不单纯是脑组织损伤时漏出所致，还与转录和翻译水平的增加有关；而血和脑脊液NSE水平的升高主要是由脑组织损伤漏出。

Abstract:

Objective To evaluate the relationship between changes of cerebrospinal fluid (CSF) or blood S - 100 protein (S- 100), neuron specific enolase (NSE) levels and the severity of hypoxic - ischernic encephalopathy (HIE), and to explore the mechanism of changes of these protein levels. Method Seven - day postnatal SD rats were used. Their serial blood and CSF S - 100 and NSE were measured by radioimmunoassay. By using the RT - PCR technique the expression of mRNA for S - 100 and NSE in the brain tissue at different gluts of time after HI injury was tested. Immunohistochemical assay was used to investigate the changes of the expression of S - 100 and NSE at the protein level. Results The values of S - 100, NSE were (1. 205 ± 0. 183) μg/L and (3. 97 ± 0. 228) ηg/ml respectively at 24 hours and (1. 235 ± 0. 097) μg/L, (3. 76 ± 0. 234) ηg/ml respectively at 48 hours in the blood, were(1. 28 ± 0. 031 ) μg/L, (7. 15 ± 0. 717) ηg/ml respectively at 24 hours and (1. 32 ± 0. 097) μg/L, (4. 29 ± 0. 144)ηg/ml respectivaly at 48 hours in the CSF after HI injury. The values of S - 100, NSE were increased significantly in both the blood and CSF samples during 24-48 hrs after HI inujry than in the control group (0. 645 ± 0. 05 μg/L, 3. 15 ± 0. 164 ηg/ml and 0. 68 ± 0. 059 μg/L, 3. 42 ± 0. 322 ηg/ml respectively). The increment corresponded well with death cell counts in the brain after HI injury; a peak of rnRNA expression of NSE exnerged at 24 hours after HI injury, while S- 100 mRNA occurred at 48 hours. The positive area of the expression of S - 100 at the protein level increased progressively during 12-96 hrs, but the expression of NSE decreased significantly with the lapse of time. Conclusions S - 100 and NSE are senstitive markers for hypoxic-ischemic brain damage(HIBD). The appropriate time for sample collection is 24 - 48 hrs after HI injury. The mechanism of S - 100 level increase in the blood and CSF after HI injury is not only due to the leakage from damaged brain cells but also through a high expression Of S - 100 mRNA and S - 100 protein, while the elevation of NSE in the blood and CSF was mainly due to the leakage from neuronal damage.