雷公藤甲素对感染性休克大鼠脑的保护作用

The protective effect of Triptolide on brain damage of rats with septic shock

目的探讨雷公藤甲素对感染性休克大鼠的脑保护作用及其可能机制。方法将SPF级SD大鼠50只,体重200-250 g,随机均分为假手术组(Sham组)、感染性休克组(LPS组)、雷公藤甲素组(TR组)、PI3K抑制剂组(LY294002组)、雷公藤甲素联合PI3K抑制剂组(TR+LY294002组)。尾静脉注射5 mg/kg脂多糖(LPS)制备大鼠感染性休克模型,TR组于造模前腹腔注射TR 200μg/kg,分别于感染性休克发生后12 h处死大鼠。HE染色观察大鼠脑组织病理变化;检测脑组织中NO、ROS、SOD及MDA水平;TUNEL法检测大鼠脑内细胞凋亡;实时PCR法检测各组大鼠脑组织中Bax、Bcl-2及Caspase-3 mRNA表达水平;Western blot法检测大鼠PI3K/Akt信号通路相关蛋白PI3K、Akt及p-Akt表达情况。结果 LPS组大鼠脑组织损伤严重,脑组织中SOD水平降低,ROS、NO及MDA水平升高。TR可以抑制LPS引发的大脑损伤及神经细胞凋亡,与LPS组相比,TR组大鼠脑组织中SOD, PI3K、p-Akt蛋白的表达水平升高,ROS、NO/MDA及Bax/Bcl-2 mRNA比率及Caspase-3 mRNA表达水平降低。但是,给予PI3K抑制剂后,TR的抗凋亡作用被抑制。结论 TR对感染性休克大鼠的脑保护作用与激活PI3K/Akt信号通路相关。

Objective To explore the protective effect of triptolide on brain damage and its possible mechanism in septic shock rat model. Methods Fifty SPF grade SD rats, weighing 200-250 g, were randomly divided into shamoperated group (Sham group), septic shock group (LPS group, injected intravenously with 5 mg/kg lipopolysaccharide), triptolide-treated group (TR group, intraperitoneally injected with 200 μg/kg TR before model formation, and sacrificed at 12 h after septic shock), PI3K inhibitor group (PI3K group) and triptolide combined with inhibitor group (TR+PI3K) group averagely. HE staining was used to observed the pathological changes of brain tissue. The level of NO, ROS, SOD and MDA in brain tissue was determined, TUNEL was used to analysis cells apoptosis, Real-time PCR was used to detect the expression of apoptic cytokines Bax, Bcl-2, Caspase-3 mRNA, Western blot was used to detect the expression of PI3K, Akt and p-Akt protein. Results LPS caused the brain tissue damage seriously, decreased SOD level, but increased ROS, NO and MDA levels in brain tissue. TR inhibited brain damage and nerve cell apoptosis caused by LPS, compared with the LPS group, SOD, PI3K、p-Akt levels increased, but expression levels of ROS, NO, MDA, Bax/Bcl-2 and Caspase 3 mRNA in brain tissue decreased in the TR group. However, after giving PI3K inhibitors, TR antiapoptotic effect was suppressed. Conclusion The protective effect of triptolide on brain damage was related to the activation of PI3K/Akt signaling pathway in rats with septic shock.