熊果酸对大鼠蛛网膜下腔出血早期脑损伤和基质金属蛋白酶-9的影响

Effect of Ursolic Acid on Early Brain Injury after Subarachnoid Hemorrhage and Matrix Metalloproteinase-9 in Rats

目的观察熊果酸对大鼠蛛网膜下腔出血(subarachnoid hemorrhage,SAH)后早期脑损伤和基质金属蛋白酶-9(matrix metalloproteinase-9,MMP-9)的影响。方法采用颈内动脉穿刺法制备大鼠SAH模型,腹腔注射给药,于SAH后24 h进行神经功能缺损评分;48 h后处死大鼠,测定脑含水量、伊文斯兰含量,明胶酶谱法检测MMP-9的活性,Real-time PCR检测MMP-9 m RNA表达水平,Western blot法检测其蛋白表达水平,尼氏染色检测脑中存活的神经元。结果与模型组相比,熊果酸给药可明显降低MMP-9活性、m RNA及蛋白表达水平;缓解神经功能缺损症状,降低脑含水量和伊文斯兰含量;改善SAH后脑内神经元减少的状况。与阳性对照(强力霉素)组比较,2组之间对MMP-9的影响无显著性差异。结论熊果酸可缓解SAH后的早期脑损伤,其作用可能与抑制脑中MMP-9的表达有关。

OBJECTIVE To explore the effect of ursolic acid（UA） on early brain injury（EBI） after subarachnoid hemorrhage（SAH） and matrix metalloproteinase（MMP）-9. METHODS The SAH model was induced by endovascular puncture. The scores of neurologic impairment were measured after SAH for 24 h. The rats in each group were executed after SAH for 48 h and the contents of water and Evans blue in brain were measured. Gelatin zymography assay was used to measure the activity of MMP-9. Real-time PCR was used to measure the expression of MMP-9 m RNA. Western blot was used to measure the expression of MMP-9 protein. Nissl staining was used to detect the survived neurons in brain. RESULTS Compared with the model control group, the activity and the expression of MMP-9 m RNA and protein signifincantly decreased in ursolic acid groups. UA also relieved the symptoms of nervous function impairment, decreased the contents of water and Evans blue in brain and improved the reduction of neurons in brain after SAH. Compared with the positive control（doxycycline） group, there was no significant difference between doxycycline and UA of the effects on MMP-9. CONCLUSION UA could promote EBI after SAH and its mechanism may be related with inhibition of the expression of MMP-9.