脑组织GDF-15水平与脑梗死大鼠血管新生以及Th1/Th2免疫平衡轴的关系

The Relationship Between Brain Tissue GDF-15 Level and Angiogenesis as well as Th1/Th2 Immune Balance Axis in Rats with Cerebral Infarction

目的:探讨脑组织GDF-15水平与脑梗死大鼠血管新生以及Th1/Th2免疫平衡轴的关系。方法:45只雄性SD大鼠随机分为脑梗死模型组、假手术组以及正常对照组,15只/组。模型组采用线栓法建立脑梗死模型,假手术组仅暴露颈内动脉后直接缝合皮肤,建模成功后1周评估大鼠改良神经功能缺损(mNSS)评分。采用HE染色检测脑组织病理学变化情况,Western blot法检测大鼠脑组织中组织生长分化因子-15(GDF-15)蛋白水平,RTPCR测定脑组织中GDF-15 mRNA水平。采用ELISA法检测脑组织INF-γ、IL-4表达情况,采用Spearman相关性分析大鼠脑组织中GDF-15蛋白、mRNA表达水平分别与mNSS评分、微血管密度(MVD)、INF-γ/IL-4水平之间的相关性。结果:模型组大鼠mNSS评分明显高于假手术组和正常对照组(P<0.001),模型组脑梗死面积比为(24.45±4.15)%,假手术组和正常对照组未发现脑梗死区域。模型组大鼠脑组织GDF-15蛋白、mRNA、MVD、INF-γ/IL-4水平均明显高于假手术组和正常对照组(P<0.05)。Spearman相关性分析显示,模型组大鼠脑组织中GDF-15蛋白、mRNA表达水平分别与mNSS评分、MVD、INF-γ/IL-4水平呈正相关关系(P<0.001)。结论:脑梗死大鼠脑组织中GDF-15处于高表达状态,且与神经功能密切关联,其作用机制可能与血管新生以及调控Th1/Th2免疫平衡轴有关。

Objective To explore the relationship between GDF-15 levels in brain tissue and angiogenesis as well as Th1/Th2 immune balance axis in rats with cerebral infarction.Methods 45 male SD rats were randomly divided into a cerebral infarction model group,a sham operation group,and a normal control group,with 15 rats per group.The model group established a cerebral infarction model using the suture method,while the sham operation group only exposed the internal carotid artery and directly sutured the skin.The improved neurological deficit(mNSS)score of the rats was evaluated one week after successful modeling.Hematoxylin-eosin staining(HE)was used to detect the histopathological changes in the brain,the protein level of tissue growth differentiation factor-15(GDF-15)was detected by Western blot,and the mRNA level of GDF-15 in the brain was determined by reverse transcription-polymerase chain reaction(RT-PCR).The expression of INF-γand IL-4 in brain tissue was detected by ELISA,and the correlation between the expression level of GDF-15 protein and mRNA in brain tissue and mNSS score,MVD and INF-γ/IL-4 level was analyzed by Spearman correlation.Results The mNSS score of the model group was significantly higher than that of the sham operation group and the normal control group(P<0.001),the ratio of cerebral infarction area was(24.45±4.15)%,and no cerebral infarction area was found in the sham operation group and the normal control group.The levels of GDF-15 protein and mRNA in brain tissue of model group were significantly higher than those in sham operation group and normal control group(P<0.05).The levels of MVD and INF-γ/IL-4 in model group were significantly higher than those in sham operation group and normal control group(P<0.05).Spearman correlation analysis showed that the expression levels of GDF-15 protein and mRNA in brain tissue were positively correlated with mNSS score,MVD and INF-γ/IL-4 levels,respectively(P<0.001).Conclusion GDF-15 is highly expressed in cerebral tissue of rats with cerebral infarction,and it is closely related to neural function,and its mechanism may be related to angiogenesis and regulation of Th1/Th2 immune balance axis.