甘草甜素调节Drd2/Cryab/NF-κB信号通路对新生大鼠缺氧缺血性脑损伤的治疗作用

Therapeutic Effect of Glycyrrhizin on Hypoxic-Ischemic Brain Damage in Neonatal Rats by Regulating Drd2/Cryab/NF-κB Signaling Pathway

目的:探究甘草甜素(GL)调节多巴胺D2受体(Drd2)/α-B晶状体蛋白(Cryab)/核转录因子-κB(NF-κB)信号通路对新生大鼠缺氧缺血性脑损伤(HIBD)的治疗作用。方法:从60只产后第7 d的新生大鼠中选取12只为假手术组,其余新生大鼠均采用Rice-Vannucci法建立HIBD新生大鼠模型。将造模成功的36只新生大鼠采用随机数字表法分为HIBD组、GL组、氟哌啶醇组(Drd2抑制剂),每组12只。对各组新生大鼠进行神经功能缺损评分及脑含水量测定;苏木素-伊红染色法(HE)及尼氏(Nissl)染色观察海马组织病理改变;脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(TUNEL)染色检测神经细胞凋亡;酶联免疫吸附法(ELISA)法检测血清中肿瘤坏死因子(TNF-α)、白细胞介素-6(IL-6)水平;免疫印记法(Western blot)检测海马组织中Drd2/Cryab/NF-κB通路蛋白表达。结果:与假手术组比较,HIBD组海马CA1结构模糊不清,神经元排列无序,尼氏小体数量减少,神经功能缺损评分、脑含水量、神经元凋亡率、TNF-α、IL-6、p-NF-κB/NF-κB蛋白表达升高,Drd2、Cryab蛋白表达降低(P<0.05);与HIBD组比较,GL组神经元排列相对整齐,尼氏小体数量增多,神经功能缺损评分及脑含水量、神经元凋亡率、TNF-α、IL-6、p-NF-κB/NF-κB蛋白表达降低,Drd2、Cryab蛋白表达升高(P<0.05);与GL组比较,氟哌啶醇组上述指标均显著逆转(P<0.05)。结论:GL可抑制HIBD新生大鼠炎症反应和神经细胞凋亡,减轻HIBD新生大鼠神经损伤,其作用机制可能与激活Drd2/Cryab/NF-κB信号通路有关。

Objective:To investigate the therapeutic effect of glycyrrhizin(GL)on hypoxic-ischemic brain damage(HIBD)in neonatal rats by regulating dopamine D2 receptor(Drd2)/α-B crystallin(Cryab)/nuclear factor-κB(NF-κB)signaling pathway.Methods:12 out of 60 neonatal rats at 7d were selected as sham operation group,and the remaining neonatal rats were used to establish the HIBD neonatal rat model by Rice-Vannucci method.36 neonatal rats with successful modeling were divided into HIBD group,GL group and haloperidol group(Drd2 inhibitor)by random number table method,with 12 rats in each group.The neurological deficit score and brain water content of neonatal rats in each group were measured.The pathological changes of hippocampus were observed by hematoxylin-eosin staining(HE)and Nissl staining.Neuronal apoptosis was detected by terminal deoxynucleotidyl transferase-mediated nick end labeling(TUNEL)staining.The levels of tumor necrosis factor(TNF-α)and interleukin-6(IL-6)in serum were detected by enzyme-linked immunosorbent assay(ELISA).The expression of Drd2/Cryab/NF-κB pathway protein in hippocampus was detected by Western blot.Results:Compared with sham operation group,the structure of hippocampal CA1 in HIBD group was blurred,the arrangement of neurons was disordered,the number of Nissl bodies was decreased,the neurological deficit score,brain water content,neuronal apoptosis rate,TNF-α,IL-6,p-NF-κB/NF-κB protein expression were increased,and the expression of Drd2 and Cryab protein was decreased(P<0.05).Compared with HIBD group,the neurons in GL group were arranged relatively neatly,the number of Nissl bodies was increased,the neurological deficit score,brain water content,neuronal apoptosis rate,TNF-α,IL-6,p-NF-κB/NF-κB protein expression were decreased,and Drd2 and Cryab protein expression were increased(P<0.05).Compared with GL group,the above indexes in haloperidol group were significantly reversed(P<0.05).Conclusion:GL can inhibit the inflammatory response and neuronal apoptosis in neonatal rats with HIBD,and reduce the nerve injury in neonatal rats with HIBD,The mechanism may be relate to the activation of Drd2/Cryab/NF-κB signaling pathway.