VEGF对新生大鼠细菌性脑膜炎病理进程的影响

The influence of vascular endothelial growth factor on the pathogenesis of neonatal rat bacterial meningitis

目的探讨血管内皮细胞生长因子(vascular endothelial growth factor,VEGF)与新生大鼠细菌性脑膜炎(bacterial meningitis,BM)发病机制的相关关系,为新生儿BM临床治疗提供新思路和实验依据。方法将150只新生大鼠按随机数字表法分为3组:正常对照组(38只)、生理盐水对照组(NS对照组,42只)和实验组(70只)。实验组经小脑延髓池注入B组链球菌Ⅲ(group B streptococcus typeⅢ,GBSⅢ)建立新生大鼠BM动物模型,NS对照组注入10μl无菌生理盐水,正常对照组不做任何处理。各组分别于≤16、>16～≤24、>24～≤48、>48～≤72h从存活新生大鼠抽取8只进行神经行为学评分、脑脊液(CSF)中的WBC计数和RT-PCR法检测脑组织中VEGFmRNA表达水平,抽取4只用免疫组织化学方法检测脑组织中VEGF蛋白表达情况。结果实验组新生大鼠在≤16、>16～≤24、>24～≤48、>48～≤72 h时均出现口唇及四肢末端发绀、呼吸困难、反应迟钝,新生大鼠在≤16 h时出现抽搐15只(Ⅳ级2只,Ⅴ级13只)、>16～≤24 h时出现抽搐41只(Ⅳ级21只,Ⅴ级20只)、>24～≤48 h时出现抽搐20只(Ⅲ级4只,Ⅳ级6只,Ⅴ级10只)、>48～≤72 h未出现抽搐。实验组新生大鼠在≤16、>16～≤24、>24～≤48、>48～≤72 h时神经行为学评分值均明显低于正常对照组、NS对照组,CSF中WBC计数值、脑组织中VEGF mRNA表达水平、脑组织中VEGF蛋白表达水平均明显高于正常对照组、NS对照组(P<0.05或P<0.01)。结论 VEGF表达异常可能与新生鼠BM发病机制相关,且在新生鼠BM的不同时期,VEGF可能起不同的作用。

Objective： To investigate the relationship between vascular endothelial growth factor（VEGF） and the pathogenesis of neonatal rat bacterial meningitis（BM）,and to provide new ideas and experimental evidence for the clinical therapy of neonatal BM.Methods： 150 Sprague-Dawley rats on postnatal day 11 were divided into 3 groups according to the random number table method： the normal control group（38 rats）,the normal saline control group（NS group,42 rats） and the experimental group（70 rats）.The experimental group was injected with group B streptococcus type Ⅲ（GBS Ⅲ） suspension to cerebellomedullary cistern,to establish the animal model for neonatal rat BM.NS control group was injected with 10 μ L sterile saline,and normal control group without any treatment.Eight rats were chosen randomly from the survival rats of each group at ≤ 16, 16～≤ 24, 24～≤ 48, 48～≤ 72 h respectively for neurological behavior assessment,cerebrospinal fluid（CSF） WBC count and RT-PCR detection of the expression of VEGF mRNA.Four rats were chosen for immunohistochemistry staining to detect the expression of VEGF protein.Results： The experimental group in ≤ 16,16～≤ 24, 24～≤ 48, 48～≤ 72 h were all cyanotic with lips and limbs,dyspneic,unresponsive,15 rats were in convulsion in ≤16 h（2 in Ⅳ grade,13 in Ⅴgrade）,41 ones were in convulsion in 16～≤24 h（21 in Ⅳ grade,20 in Ⅴgrade）,20 ones were in convulsion in 24～≤48 h（4 in Ⅲ grade,6 in Ⅳ grade,10 in Ⅴgrade） 、while no rats were in convulsion 48～≤72 h.The experimental group in ≤16,16～≤ 24, 24～≤ 48, 48～≤ 72 h neurological behavior score was significantly lower than that in normal control group,NS control group,WBC count in CSF,VEGF mRNA and VEGF protein expression level in brain tissue were all significantly higher than those in the normal control group and the NS control group（P 0.05 or P 0.01）.Conclusion： The abnormal expression of VEGF may be associated with the pathogenesis of neonatal rat BM,and in different periods of neonatal rat BM,VEGF may play a different role.