Aβ_(1-40)海马注射对大鼠神经胶质细胞S100β和iNOS表达的影响

Changes of S100β and iNOS expression after β-amyloid injection into hippocampus

目的 在体条件下观察 β-淀粉样蛋白 (Aβ)对 S10 0 β和诱导型一氧化氮合酶 (i NOS)表达的影响 ,探讨三者之间的相互关系。方法 以不同浓度 Aβ1 - 4 0 溶液及生理盐水做海马立体定向注射后 ,采用刚果红染色、尼氏染色及免疫组织化学方法 ,显示胶质细胞反应、神经元损伤情况及 S10 0 β、i NOS表达变化。结果 胶质细胞增生与神经元缺失程度以及 S10 0 β与 i NOS的表达水平均随 Aβ1 - 4 0 浓度增大而增加 ,4μg/ μl Aβ溶液注射组 S10 0 β阳性细胞数 (个 /视野 )为 42 .39± 3.46 ,显著多于盐水对照组 (34.5 0± 3.5 7) ,P<0 .0 1;i NOS阳性染色面积与 S10 0 β阳性细胞数存在较强的相关性 (r=0 .873)。结论 在体条件下高含量 Aβ强烈诱导胶质细胞 S10 0 β和 i NOS的表达 ,结果提示三者之间的相互作用在 Alzheimer病发病机制中有重要作用。

Objective To observe the effect of β amyloid (Aβ) on S100β and inducible nitric oxide synthase(iNOS) expression in vivo and to explore the relations among Aβ,S100β and iNOS. Methods One week after sterotaxis injection into CA 1 subregion of hippocampus with different doses of Aβ 1 40 and normal saline,we evaluated the glial cell reaction,neuronal damage and the expression of S100β and iNOS by means of Congo red staining,Nissle staining and immunohistochemical assays. Results The gliosis level,neuronal reductions and the numbers of S100β positive cells increased with elevation of Aβ 1 40 dosage. iNOS like immunoreactivity(iNOS LIR) cells were not found in any brain region of normal or saline injected rats. After Aβ 1 40 injection,the rats showed a dose dependent increase in expression of iNOS at or around the injection site. Furthermore,the expression of iNOS was remarkably correlated with the S100β level (r=0.873,P<0.001). Conclusion Aβ 1 40 can induce glial cells high expression of S100β and iNOS in vivo. It suggestes that the synergisms among the three proteins should be important in the pathogenesis of Alzheimer's disease.