灯盏花乙素调节cGAS/STING信号通路对创伤性脑损伤大鼠神经炎症的影响

Effects of scutellarin on neuroinflammation in rats with traumatic brain injury by regulating cGAS/STING signaling pathway

目的 探讨灯盏花乙素(Scu)改善创伤性脑损伤(TBI)大鼠神经炎症的作用及机制。方法 采用改良Feeney法构建TBI大鼠模型。将成模大鼠随机分为TBI组、Scu低剂量组(40 mg/kg)、Scu高剂量组(80 mg/kg)和环鸟苷酸-腺苷酸合成酶(c GAS)抑制剂组(cGAS抑制剂RU.521,450μg/kg),每组24只;另取24只大鼠作为假手术组。采用改良神经功能缺损评分(mNSS)法评估大鼠神经功能;以干/湿比重法测定大鼠脑含水量;以苏木素-伊红、原位末端标记染色法观察大鼠脑组织病理学变化和细胞凋亡情况;采用酶联免疫吸附检测法测定大鼠脑组织中β干扰素(IFN-β)、CXC趋化因子配体10(CXCL10)、肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)含量;以Western blot法检测大鼠脑组织中cGAS/干扰素基因刺激蛋白(STING)信号通路相关蛋白的表达情况。结果 与假手术组比较,TBI组大鼠的m NSS,脑含水量,脑组织细胞凋亡率,IFN-β、CXCL10、TNF-α、IL-6含量和cGAS、STING蛋白相对表达水平均显著升高(P<0.05);脑组织存在水肿、出血、神经元病理学损伤。与TBI组比较,各给药组大鼠的上述指标及病理变化均显著改善(P<0.05),且Scu的作用具有剂量依赖性(P<0.05),而Scu高剂量组和c GAS抑制剂组大鼠上述指标比较差异均无统计学意义(P>0.05)。结论 Scu可能通过抑制cGAS/STING信号通路激活来减轻TBI大鼠神经炎症,减少其脑组织损伤及细胞凋亡,促进其神经功能恢复。

OBJECTIVE To investigate the improvement effects and mechanism of scutellarin(Scu) on neuroinflammation in rats with traumatic brain injury(TBI).METHODS The modified Feeney method was applied to construct TBI rat model.The rats were randomly grouped into TBI group,Scu low-dose group(40 mg/kg),Scu high-dose group(80 mg/kg),cyclic guanylateadenylate synthase(cGAS) inhibitor group(cGAS inhibitor RU.521,450 μg/kg),with 24 rats in each group.Other 24 rats were included in the sham operation group.The modified neurological deficit score(mNSS) method was applied to assess the neurological function of rats;the brain water content of rats was measured by dry/wet specific gravity method;hematoxylin-eosin and TdT-mediated dUTP nick-end labeling staining were applied to observe the pathological changes and apoptosis of brain tissue in rats;the levels of interferon-β(IFN-β),CXC chemokine ligand-10(CXCL10),tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) in rat brain tissue were detected by enzyme-linked immunosorbent assay;Western blot method was applied to detect the expression of cGAS/interferon gene stimulating protein(STING) signal pathway-related proteins in brain tissue of rats.RESULTS Compared with the sham operation group,the m NSS,brain water content,apoptosis rate,the contents of IFN-β,CXCL10,TNF-αand IL-6,and the relative expressions of cGAS and STING proteins in TBI group increased significantly(P<0.05);there were edema,bleeding and pathological damage to neurons in the brain tissue.Compared with TBI group,the above indicators and pathological changes of rats in administration groups were improved significantly(P<0.05),and the effect of Scu was in a dosedependent manner(P<0.05);however,there was no statistically obvious difference in the above indicators between the Scu high-dose group and the c GAS inhibitor group(P>0.05).CONCLUSIONS Scu may alleviate neuroinflammation,reduce brain tissue damage and apoptosis,and promote the recovery of neural function in TBI rats by inhibiting the activation of c GAS/STING signaling pathway.