复合益生菌制剂缓解cuprizone诱导的小鼠神经脱髓鞘

Compound probiotics alleviate cuprizone-induced demyelination in mice

摘要:

【目的】探索复合益生菌制剂对双环己酮草酰二腙（cuprizone，CPZ）诱导的小鼠脑内神经脱髓鞘的作用。【方法】将27只小鼠随机分为正常组（NC）、模型组（CPZ）和益生菌处理组（probiotics）。NC组小鼠正常饲喂，CPZ组和probiotics组小鼠饲喂含0.2% CPZ的饲料且每天分别灌饲0.2 mL生理盐水及同体积（75亿菌落形成单位活菌）的复合益生菌制剂，6周后处死小鼠。通过快蓝染色（LFB）观察小鼠脑内神经髓鞘的完整性；苏木素-伊红染色（HE）、阿利新蓝染色及免疫荧光染色分别评估回肠及结肠组织病理学改变、黏蛋白的表达及紧密连接蛋白ZO-1、occludin的表达；ELISA检测脑组织匀浆脂多糖LPS水平；Western blotting检测脑组织TLR4/NF-κB信号通路的蛋白表达。【结果】与CPZ组相比，复合益生菌制剂干预后，发生在CPZ组小鼠大脑胼胝体内的神经脱髓鞘明显减少；回肠绒毛排列整齐致密，结肠腺体增多，炎细胞浸润减少，黏蛋白及紧密连接蛋白表达均增加；脑组织LPS水平显著降低，TLR4、NF-κB及P-IκB/IκB蛋白表达量下降。【结论】复合益生菌制剂可能通过降低肠壁通透性缓解CPZ诱导的小鼠中枢神经系统脱髓鞘。

Abstract:

[Objective] To explore the effects of compound probiotics on demyelination of the mice induced by bis-cyclohexanone-oxalyldihydrazone (cuprizone, CPZ).[Methods] Twenty-seven mice were randomly assigned into normal (NC) group, model (CPZ) group, and probiotics group. The mice in the NC group were fed with normal diet, and those in the CPZ group and probiotics group with the diet containing 0.2% CPZ. The mice in the CPZ group and probiotics group were fed with 0.2 mL normal saline and 0.2 mL compound probiotics (7.5 billion colony-forming units) per day, respectively. All the mice were sacrificed after 6 weeks. Luxol fast blue (LFB) staining was employed to observe myelin sheath in the cerebrum. The histopathological change and the expression of mucin and tight junction proteins (ZO-1 and occludin) in ileum and colon were detected by hematoxylin-eosin (HE) staining, Alcian blue staining, and immunofluorescence staining, respectively. The content of lipopolysaccharide (LPS) in brain homogenate was detected by ELISA. The expression of proteins involved in the Toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) signaling pathway was detected by Western blotting.[Results] Compared with the CPZ group, compound probiotics significantly alleviated the demyelination in corpus callosum. In addition, the mice in the probiotics group showed neat and dense ileum villi, increased colon glands, decreased infiltration of inflammatory cells, and up-regulated expression of mucin and tight junction proteins, declined LPS level, and down-regulated expression of TLR4, NF-κB, and P-IκB/IκB in the brain.[Conclusion] Compound probiotics may alleviate CPZ-induced demyelination in mice by reducing intestinal wall permeability.