五味子乙素对大鼠脑缺血再灌注损伤的保护作用及其机制

目的：观察五味子乙素（SchB）对大鼠脑缺血再灌注损伤的保护作用及对HSPA12B/PI3K/Akt信号通路的影响，并探讨其作用机制。方法：将130只SD大鼠随机分为假手术组、脑缺血再灌注损伤模型组（模型组）、低剂量五味子乙素组（SchB 3 mg·kg^-1，SchB₁组）、中剂量五味子乙素组（SchB 10 mg·kg^-1，SchB₂组）和高剂量五味子乙素组（SchB 30 mg·kg^-1，SchB₃组）。假手术组大鼠不插栓线；模型组大鼠建立脑缺血2 h再灌注22 h模型；SchB₁、SchB₂和SchB₃组分别用不同剂量的SchB预先给药7 d后再造模。神经功能缺损评分检测大鼠神经功能障碍情况，通过脑组织含水量的测定检测脑组织水肿情况，甲苯胺蓝染色检测脑组织形态学改变，ELISA法检测脑组织匀浆中核因子kappa B（NF-κB）、肿瘤坏死因子α（TNF-α）、白细胞介素1（IL-1）和白细胞介素6（IL-6）水平，Western blotting法检测脑组织中热休克蛋白A12B（HSPA12B）、丝氨酸/苏氨酸蛋白激酶（Akt）和磷酸化的丝氨酸/苏氨酸蛋白激酶（p-Akt）表达水平。结果：与假手术组比较，模型组大鼠神经功能评分明显升高（P<0.01），脑组织含水量升高（P<0.01），脑组织结构疏松，间质出现水肿，NF-κB、TNF-α、IL-1和IL-6水平升高（P<0.01），HSPA12B和p-Akt蛋白表达水平降低（P<0.01）；与模型组比较，SchB₁、SchB₂和SchB₃组大鼠神经功能评分明显降低（P<0.01），SchB₂和SchB₃组脑组织含水量减少（P<0.05），神经细胞水肿减轻，空泡减少，NF-κB、TNF-α、IL-1和IL-6水平降低（P<0.05或P<0.01），SchB₂和SchB₃组HSPA12B蛋白表达水平升高（P<0.05），SchB₁、SchB₂和SchB₃组p-Akt蛋白表达水平升高（P<0.01）。结论：SchB对大鼠脑缺血再灌注损伤具有一定的保护作用，其机制可能与调控HSPA12B/PI3K/Akt信号通路、抑制再灌注时炎症反应对神经细胞的损伤有关。

Protective effect of schisandrin B on cerebral ischemia reperfusion injury of rats and its mechanisms

Objective:To investigate the protective effect of schisandrin B (SchB)on the cerebral ischemia reperfusion injury of the rats and the influence in HSPA12B/PI3K/Akt signaling pathway,and to explore the mechanisms.Methods:130 SD rats were divided into sham group,cerebral ischemia reperfusion injury model group (model group),low dose of SchB group (SchB 3 mg· kg-1 ,SchB1 group),middle dose of SchB group (SchB 10 mg·kg-1 ,SchB2 group)and high dose of SchB group (SchB 30 mg·kg-1 ,SchB3 group)(n=26).The rats in sham group didn’t plug lines;the rats in model were used to establish ischemia reperfusion models;the rats in SchB1 ,SchB2 and SchB3 groups were firstly pretreated with different doses of SchB for 7 d,and then they were used to build cerebral ischemia reperfusion injury models.The nerve dysfunction of rats was evaluated by neurologic deficit score.The cerebral edema was detected by measuring the content of water in brain tissue.The morphological changes of brain tissue were observed by toluidine blue staining.The levels of nuclear factor kappa B (NF-κB), tumor necrosis factor-α(TNF-α),interleukin-1 (IL-1)and interleukin-6 (IL-6)in the brain tissue were detected by ELISA.Western blotting method was used to detect the protein expression levels of heat shock protein A12B (HSPA12B ), serine-threonine kinase (Akt ) and phosphorylation serine-threonine kinase (p-AKT ). Results:Compared with sham group,the neurologic deficit score of rats in model group was significantly increased (P <0.01),and the content of water in brain tissue was increased (P < 0.01 );the brain tissue structure was loosened,and the mesenchyme appeared edema;the NF-κB,TNF-α,IL-1,and IL-6 levels were increased (P <0.01),and the expression levels of HSPA12B and p-Akt proteins were decreased (P <0.01).Compared with model group,the neurologic deficit scores of the rats in SchB1 ,SchB2 ,and SchB3 groups were decreased (P <0.01),and the contents of water in brain tissue of the rats in SchB2 and SchB3 groups were decreased (P <0.05);the edema of nerve cells was alleviated,and the cavities were reduced;the NF-κB,TNF-α,IL-1,and IL-6 levels were decreased (P <0.05 or P <0.01),the expression levels of the HSPA12B protein in SchB2 ,and SchB3 groups were increased (P <0.05),and the p-Akt protein expression levels of the rats in SchB1 ,SchB2 ,and SchB3 groups were increased (P <0.01).Conclusion:SchB could protect the cerebral ischemia reperfusion injury of rats,its mechanism may be related to regulating the HSPA12B/PI3K/Akt signaling pathway and inhibiting the inflammatory reaction damage to the nerve cells of reperfusion.