小檗碱对大鼠脑缺血/再灌注损伤的保护作用及免疫机制*

目的:探讨小檗碱对大鼠脑缺血/再灌注损伤的保护作用及免疫机制。方法:50只SD大鼠随机分为假手术组(Sham group)、模型组(Model group)、小檗碱低剂量组(BBR-L,25 mg/kg)、小檗碱中剂量组(BBR-M,50 mg/kg)、小檗碱高剂量组(BBR-H,100 mg/kg),每组各10只。采用Longa线栓法建立脑缺血/再灌注大鼠模型,缺血2 h后再灌注24 h处理。于造模成功2 h后灌胃给药,假手术组和模型组组按上述方法同体积给予生理盐水。给药24 h后,测定各组大鼠神经功能缺损程度评分及脑梗死率;采用ELISA法检测抗氧化酶SOD和GSH-Px的活性、细胞因子TNF-α、IFN-β、IL-6和NO的含量;采用流式细胞术检测CD4⁺、CD8⁺及CD4⁺/CD8⁺血清含量;进一步采用RT-qPCR与Western blot技术检测大鼠脑组织内NF-κB-NLRP3信号轴关键基因及蛋白的表达情况。结果:与假手术组比较,模型组大鼠神经功能缺损程度、脑梗死率均升高(P＜0.05),且血清NO、TNF-α、IFN-β、IL-6含量和脑组织的NF-κB p65、NLRP3、ASC及caspase-1基因与蛋白表达水平均升高(P＜0.05),而血清中SOD、GSH-Px活性和CD4⁺、CD8⁺及CD4⁺/CD8⁺水平下降(P＜0.05);与模型组比较,BBR-H、BBR-M、BBR-L组大鼠神经功能缺损程度、脑梗死率均下降(P＜0.05),且血清NO、TNF-α、IFN-β、IL-6含量和脑组织的NF-κB p65、NLRP3、ASC及caspase-1基因与蛋白表达水平均降低(P＜0.05),而血清中SOD、GSH-Px活性和CD4⁺、CD8⁺及CD4⁺/CD8⁺水平升高(P＜0.05)。结论:小檗碱可通过减轻氧化应激,抑制炎症反应,增强免疫功能,减轻大鼠脑缺血/再灌注损伤,其机制可能与抑制NF-κB-NLRP3信号有关。

Protective effect and immune mechanism of berberine on cerebral ischemia/reperfusion injury in rats

Objective: To investigate the protective effect and immune mechanism of berberine on cerebral ischemia/reperfusion injury in rats. Methods: Fifty SD rats were randomly divided into sham operation group (Sham), model group (Model), berberine low dose groups (BBR-L, 25 mg/kg), berberine medium dose groups (BBR-M, 50 mg/kg) and berberine high dose groups (BBR-H, 100 mg/kg), with 10 rats in each group. Longa suture method was used to establish a rat model of cerebral ischemia/reperfusion, after 2 hours of ischemia, reperfusion for 24 hours. Rats in BBR-L, BBR-M and BBR-H were treated with berbrerine by gavage 2 hours after successful model building, while the sham operation group and the modle group were given the same volume of saline as described above. After 24 hours of administration, the activity of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), cytokine tumor necrosis factor α (TNF-α) , interferon β (IFN-β) , interleukin 6 (IL-6) and nitric oxide (NO) content were detected by ELISA assay. Serum CD4⁺, CD8⁺ and CD4⁺/CD8⁺ contents were measured by flow cytometry to investigate the immune function of each group. RT-qPCR and Western blot were used to detect NF-kappaB-NOD-like receptors 3 (NF-κB-NLRP3) signal axis key genes and protein expression in rat brain tissue. Results: Compared with the sham operation group, the degree of neurological deficit and the rate of cerebral infarction were increased in the model group (P＜0.05), and the levels of serum NO, TNF-α, IFN-β, IL-6, NF-κB p65, NLRP3, ASC and caspase-1 in brain tissue were increased (P＜0.05), while the activities of SOD, GSH-Px and the levels of CD4⁺, CD8⁺ and CD4⁺/CD8⁺ in serum were decreased (P＜0.05). Compared with the model group, the degree of neurological deficit and the rate of cerebral infarction were increased in the BBR-H, BBR-M and BBR-L groups (P＜0.05), and the levels of serum NO, TNF-α, IFN-β, IL-6, NF-κB p65, NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1 in brain tissue were increased (P＜0.05), while the activities of SOD, GSH-Px and the levels of CD4⁺, CD8⁺ and CD4⁺/CD8⁺ in serum were decreased (P＜0.05). Conclusion: Berberine may reduce oxidative stress, inhibit inflammation, enhance immune function, and reduce cerebral ischemia/reperfusion injury in rats, which may be related to the inhibition of NF-κB-NLRP3 signaling.