大鼠脊髓缺血再灌注损伤后神经元Tau蛋白及磷酸化-Tau蛋白表达的变化研究

Changes in expression of Tau protein and phosphorylated Tau protein in neurons after spinal cord ischemia-reperfusion injury in rats

目的观察脊髓缺血再灌注损伤(SCII)后神经元Tau蛋白与磷酸化-Tau(p-Tau)蛋白表达的变化。方法取健康成年SD大鼠96只,随机分为假手术(仅建模不制造损伤)组(n=48)及SCII(制造SCII模型)组(n=48)。建模后均于3、6、12、24、48、72 h(n=8)取L4~L5节段脊髓进行免疫组织化学染色以观察脊髓神经元凋亡情况,并比较假手术组与SCII组间及同一个组内各个时间点Tau蛋白、p-Tau蛋白的表达。结果假手术组细胞完整,灰质部分细胞密集,少数细胞内可见Tau蛋白表达,细胞核周及细胞质少量丝状p-Tau蛋白表达,Tau蛋白和p-Tau蛋白表达量在各个时间点间比较差异均无统计学意义(P>0.05)。SCII组凋亡细胞间可见散在的Tau蛋白阳性表达,未凋亡细胞内可见明显的强阳性表达;Tau蛋白表达量在损伤后逐渐增加,48 h达到峰值,72 h趋于平稳;除72 h外,各时间点间两两比较差异均有统计学意义(P<0.05)。SCII组在各凋亡细胞细胞质间可见条索状及片状p-Tau蛋白阳性表达;p-Tau蛋白表达量在6 h内迅速增高,6 h后未见明显变化,其后各时间点间两两比较差异均无统计学意义(P>0.05)。各时间点SCII组的Tau蛋白和p-Tau蛋白表达量组均高于假手术组,差异有统计学意义(P<0.05)。结论SCII后6~48 h内调控Tau蛋白和p-Tau蛋白的表达有望减轻脊髓损伤的严重程度。

Objective To explore the changes in the expression of Tau protein and phosphorylated Tau(p-Tau)protein in neurons after spinal cord ischemia-reperfusion injury(SCII).Methods Ninety-six healthy adult SD rats were randomly divided into a sham operation group(n=48)and a SCII group(n=48).Based on the reperfusion time of 3 h,6 h,12 h,24 h,48 h and 72 h,the SCII group was divided into 6 subgroups(n=8 per subgroup).Immunohistochemical staining was used to observe the apoptosis of spinal cord neurons in the L4-L5 segments and the expression of Tau protein and p-Tau protein.Results In the sham operation group,the neuron cells were intact,mainly concentrated in the gray matter.Tau protein was seen in a small number of neuron cells,and a small amount of filamentous p-Tau protein in the pernucleus and cytoplasm.There was no significant difference between Tau protein and p-Tau protein expression in neurons at each time point(P>0.05).In the SCII group,scattered Tau protein was seen in the apoptotic cells while there was a strong positive expression of Tau protein in the non-apoptotic cells.The expression of Tau protein in the SCII group gradually increased after injury,reaching a peak at 48h and plateauing at 72 h,and was significantly different between any 2 time points(except for 72 h)(P<0.05).In the SCII group,the positive expression of p-Tau protein was observed in the cytoplasm of the apoptotic cells in strips and sheets.It increased rapidly within 6 h but did not change significantly after 6 h,showing no significant difference between any 2 time points afterwards(P>0.05).There was a statistically significant difference in the expression of Tau protein and p-Tau protein between the SCII group and the sham operation group at each time point(P<0.05).Conclusion It is hopeful to reduce the severity of spinal cord injury by regulating the expression of Tau protein and p-Tau protein within 6 to 48 hours after SCII.