肺炎链球菌性脑膜炎小鼠B7-H3蛋白对巨噬细胞炎性蛋白2mRNA表达的影响

Effect of B7-H3 protein on the expression of macrophage-inflammatory protein 2 mRNA in Streptococcus pneumococcal meningitis mouse models

目的探讨协同信号分子B7-H3对肺炎链球菌性脑膜炎小鼠模型中炎性趋化因子巨噬细胞炎性蛋白2（MIP-2）mRNA表达的影响。方法1．5～2．0个月健康雄性BALB／C小鼠48只，随机分为4组：9g／L盐水组（Ns组）、B7-H3蛋白组（B7-H3组）、肺炎链球菌组（SP组）、肺炎链球菌＋B7-H3蛋白组（联合组），每组12只；经小鼠侧脑室穿刺分别注入9g／L盐水、B7-H3蛋白、肺炎链球菌3型、肺炎链球菌3型＋B7-H3蛋白建立动物模型。注射后6、24h依据loeffler5分制评分方法对各组小鼠进行神经行为评分，然后麻醉处死小鼠，取脑组织，用Real—timePCR方法检测小鼠脑组织内MIP-2mRNA的相对表达量。应用SPSS18．0软件进行统计学分析。结果侧脑室穿刺注射6、24h后各组小鼠神经行为学评分结果：B7-H3组神经行为评分与NS组比较差异无统计学意义（P〉0．05）；SP组评分较NS组明显降低，差异具有统计学意义（P〈0．05）；联合组较sP组评分更明显降低，差异具有统计学意义（P〈0．05）。Real—timePCR方法检测结果：sP组在注射6h后MIP-2mRNA的相对表达量较NS组升高[（1．210±0．932）比（1．000±0．008）]，但差异无统计学意义（P〉0．05）；在注射24h后sP组MIP-2mRNA的相对表达明显高于Ns组[（12．880±7．792）比（1．000±0．091）]，差异具有统计学意义（P〈0．05）；联合组与sP组比较：6hMIP-2相对表达量增高[（1．240±0．804）比（1．210±0．932）]，但无统计学差异（P〉0．05），24h相对表达量明显升高[（38．760±6．061）比（12．880±7．792）]，差异具有统计学意义（P〈0．05）。结论在肺炎链球菌性脑膜炎模型中，协同信号分子B7-H3使炎性趋化因子MIP-2mRNA的表达上调，促进病情进展。

Objective To investigate the effect of B7-H3 protein, a collaborative signal molecule,on macro- phage-inflammatory protein 2 （MIP-2） mRNA level in Streptococcus pneumococcal meningitis mouse models. Methods Forty-eight healthy male BALB/C mice at the age of 1.5 -2.0 months were randomly divided into 4 groups：9 g/L saline group （ NS group） , B7-H3 protein group （ BT-H3 group ） , Streptococcus pneumoniae group （ SP group） , and Strep- tococcus pneumoniae plus B7-H3 protein group（ combination group） , 12 mice in each group. Mouse models were estab- lished by intracerebral ventricular injection with 9 g/L saline, B7-H3 protein, Streptococcus pneumoniae type 3 or Strep- tococcus pneumoniae type 3 plus B7-H3 protein. Neurobehavior of different groups was evaluated according to loeffler nile after injection for 6 h and 24 h, then the mice were sacrificed and MIP-2 mRNA levels were tested by Real - time PCR. The results were analyzed by SPSS 18.0 software. Results Neurobehavior scoring results showed that there were no significant differences between B7-H3 group and NS group （ P 〉 0.05 ） after infection for 6 h and 24 h, while the score of SP group was decreased compared with that of NS group （P 〈 0.05 ） , and the score of combination group was significantly decreased compared with that of SP group （ P 〈 0.05 ）. Real - time PCR results showed that, compared with the NS group, the relative MIP-2 mRNA level in SP group increased after injection for 6 hours （1. 210±0. 932 vs 1. 000±0. 008 ） , but the difference was not significant （ P 〉 0.05 ）, while at 24 h post infection, the relative MIP-2 mRNA expressions in SP group were significantly increased compared with that of NS group（ 12.880±7. 792 vs 1. 000±0. 091 ） ,the difference was significant （P 〈 0.05 ）. At 6 h post infection, SP ＋ B7-H3 treatment enhanced the MIP-2 mRNA production compared to SP infection alone, but the difference was not significant [ （ 1. 240±0. 804 ） vs （ 1. 210±0.932 ） ] （ P 〉 0.05 ） ; while at 24 h post infection, the difference was significant （ 38. 760±6. 601 vs 12. 880 ±7. 792） （ P 〈 0.05 ）. Conclusion Collaborative signal molecule B7-H3 protein may increase MIP-2 mRNA level in Streptococcus pneumococcal meningitis mouse model, and exaggerate the clinical disease condition.