蜱传脑炎病毒感染引起脑组织星形胶质细胞活化和RANTES表达水平升高

Tick-borne encephalitis virus infection caused astrocyte activation and increased RANTES expression in brain tissue

目的通过研究蜱传脑炎病毒(tick-borne encephalitis virus,TBEV)感染小鼠引起神经退行性疾病探讨中枢神经系统可能存在的致病机制。方法小鼠颅内接种TBEV,8 d后处死取脑组织,HE染色观察脑组织病变以验证造模成功;免疫组化检测小鼠脑组织内神经元细胞核(neuronal nuclei,NeuN)、胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)、增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)和调节激活正常T细胞表达和分泌因子(reduced upon activation,normal T cell expressed and secreted,RANTES)的表达,统计阳性细胞数量或分析灰度值计算评分;免疫荧光结合激光共聚焦观察NeuN、GFAP的阳性细胞分布和RANTES、PCNA的表达情况。结果TBEV感染后小鼠脑组织NeuN阳性细胞数减少,GFAP阳性细胞数增加,星形胶质细胞增殖多于神经元,且RANTES主要由星形胶质细胞产生。结论TBEV感染会引起脑组织的神经毒性反应,导致神经细胞死亡,星形胶质细胞活化并产生大量趋化因子RANTES。

Objective To explore the possible pathogenic mechanism of the central nervous system by studying the neurodegenerative diseases caused by tick-borne encephalitis virus(TBEV)infection in mice.Methods The mice were intracranially inoculated with TBEV,8 days later the mice were sacrificed,the brain tissues of all mice were collected and observed after HE staining to verify if the model was successfully established;the expressions of neuronal nuclei(NeuN),glial fibrillary acidic protein(GFAP),proliferating cell nuclear antigen(PCNA)and reduced upon activation,normal T cell expressed and secreted(RANTES)in mouse brain tissue were detected by immunohistochemical method,the number of positive cells was counted and the gray value was analyzed to calculate the score.Immunofluorescence combined with laser scanning confocal microscopy were used to observe the distribution of NeuN and GFAP positive cells and the expression of RANTES and PCNA.Results The number of NeuN-positive cells in the brain tissue of mice infected with TBEV decreased,while the GFAP-positive cells increased.Furthermore,astrocytes proliferated faster than neurons,and RANTES was mainly produced by astrocytes.Conclusions TBEV infection could cause neurotoxic reactions in brain tissue,leading to nerve cells death and activating astrocytes which produces many RANTES.