中文摘要：

目的探讨结核分枝杆菌感染对人星形胶质细胞基质金属蛋白酶（MMP）-9表达的影响及其机制。方法分别用结核分枝杆菌（MTB）直接感染人星型胶质细胞系U251细胞，MTB感染外周血单个核细胞（PBMC）后的条件培养基（CoMTB）、含RPMI-1640的MTB条件培养基（CoTB）及未感染MTB的PBMC条件培养基（CoMCON）刺激U251细胞，ELISA检测细胞上清液中MMP-9含量，明胶酶谱法检测MMP9活性，Western印迹法检测MMP-9、核因子（NF）-κB及核因子-κB抑制蛋白（IκB）α和IκBβ的表达。组间及配对数据比较采用t检验，多组间比较先行方差齐性检验，方差齐采用方差分析，不齐采用秩和检验。结果MTB直接感染U251细胞后MMP-9几乎检测不到，CoMTB刺激U251细胞后，MMP-9含量从12h的（400．1±12．6）pg／mL逐步升至72h的（2900．3±108．4）pg／mL，呈时间依赖性；而CoMCON和CoTB组刺激72h后MMP-9含量分别为（300．8±40．4）pg／mL和（400．2±42．8）pg／mL，差异有统计学意义（t=9．514，P=0．000；￡-9．476，P=0．000）。明胶酶谱法和Western印迹法检测CoMTB组上清液中MMP-9的表达，随刺激时间延长，其活性和表达量逐渐增强，与ELISA法一致。CoMTB刺激U251细胞后NF-κBP65表达增加，1h时是CoMCON组的2倍（t=6．78，P=0．041），2h时是CoMCON组的5倍（t=9．23，P=0．008），CoMTB组ICBa和IκBα蛋白0．5h开始降解并持续至6h，而CoMCON组未见降解。结论PBMC-神经胶质细胞网络在结核感染的基质降解中起重要作用，CoMTB可能通过激活NF-κB信号通路上调MMP9的表达。

英文摘要：

Objective To explore the impact of Mycobacterium tuberculosis （M. tb） infection on the expression of matrix metalloproteinase （MMP）-9 in human astrocyte cell line and its mechanism. Methods Human astrocyte cell line U251 cells were stimulated by direct M. tb infection, conditioned mediums of M. tb-infected peripheral blood mononuelear cells （PBMC, CoMTB）, incubation M. tb monocyte-free medium （CoTB） and PBMC not infected with M. tb （CoMCON）, respectively. Enzyme- linked immunosorbent assay （ELISA） and Gelatin zymography were used to detect cell supernatant content and activity of MMP-9, respectively. Western blot assay was used to detect the proteinexpressions of MMP-9, nuclear factor （NF） κB, and inhibitory subunits of NF κB （IκBα and IκBβ）. Comparisons between two groups or paired results were performed by student t-test, and comparison among multipie groups was performed by homogeneity test of variance （analysis of variance rather than rank sum test）. Results U251 cells stimulated with direct M. tb infection, expressed undetectable of MMP-9, while after stimulation by CoMTB, MMP-9 content gradually increased from （400.1±12.6） pg/mL at 12 h to （2900.3±108.4） pg/mL at 72 h time-dependently. MMP-9 contents in CoMCON and CoTB groups at 72 h were （300.8±40.4） pg/mL and （400.2±42.8） pg/mL, respectively, with statistical significance （t=9. 514, P=0. 000; t= 9. 476, P= 0. 000）. Activity and expression of MMP 9 increased over time in supernatant of CoMTB group measured by Gelatin zymography and Western blot assay, which were consistent with the results of ELISA. NF-κB P65 began to increase after 30 min of CoMTB, compared with CoMCON. NFκB P65 expression inducing a 2-fold increase after 1 h and 5-fold incoase after 2 h, and continued to increase until 6 h. Degradation of IκBα and IκBβ in CoMTB group started from 0.5 h, and persisted until 6 h, which was not observed in CoMCON group. Conclusions The results suggest that PBMC-dependent cytokine netw