苦参素对实验性自身免疫性脑脊髓炎大鼠TLR4/MD-2表达的影响

Effect of matrine on TLR4/MD-2 of experimental autoimmune encephalomyetic rats

目的:观察苦参素对实验性自身免疫性脑脊髓炎(EAE)大鼠脊髓中Toll样受体-4(TLR4)和血清中髓样分化蛋白-2(MD-2)表达的影响,探讨苦参素对EAE大鼠的防治机制。方法:用豚鼠全脊髓匀浆和完全弗氏佐剂制成的抗原乳剂复制EAE模型,将50只大鼠随机分为正常组、模型组、苦参素高、中、低剂量组(250、200、150 mg/kg),连续给药16天,同期模型组和正常组腹腔注射等量生理盐水,观察记录大鼠体重变化,神经功能学评分,苏木素-伊红(HE)和变色酸2R-亮绿(C-2R-BG)染色观察病理改变、RT-PCR法检测脊髓中TLR4的表达、ELISA法测定EAE大鼠血清中MD-2含量的变化。结果:苦参素起效剂量为41.67mg/kg,半数致死量为353.5mg/kg,苦参素150、200、250mg/kg能延迟大鼠EAE的发病时间,明显降低EAE大鼠的神经功能学评分,减轻EAE大鼠中枢神经系统炎症浸润和髓鞘脱失,下调脊髓中TLR4的表达,降低血清中MD-2的含量,且高中低三剂量组间的差异有统计学意义。结论:苦参素对EAE大鼠有防治作用,其作用机制可能与下调大鼠脊髓中TLR4和血清中和MD-2的表达有关。

We observed the effect of matrine on the expression of Toll-like receptor 4 （TLR4） and myeloid differentiation factor-2（MD-2） in experimental autoimmune encephalomyetic（ EAE ）rats. To investigate the possible mechanism of matrine for the prevention and treatment of EKE rats and provide clinical proof. Methods： The EKE models were induced by immuned spinal cord extracts of guinea pig with complete Freunds adjuvant. Then we divide 50 Wistar rats into five groups randomly： normal group, model group, three matrine -treated groups（ 150,200,250mg/kg ）. Rats of MAT-treated groups were injected intraperitoneally with MAT daily for 16 days , while rats of normal group and model group were injected intraperitoneally with normal saline , at the same time, we observed body weights,clinical signs daily. We through hematoxylin- eosin（ H＆ E） and chromotrope 2R - brilliant green（ C- 2R- BG）to analyse histopathologlcal of spinal cord. TLR4 in spinal cord were determined by RT- PCR. ELISA was used to detect MD-2 in serum level. Results： The effective dose of matrine is 41. 67mg/kg and the LDs0 of matrine is 353.5mg/kg, during the effective range, matrine could put off the morbidity, decrease neurological scores significantly and inflammatory infiltration and demyelination in central nervous system of EAE rats. Furthermore, the expression of TLR4 and serum level of MD-2 were reduced; and the differences of the expression of TLR4 and MD-2 between three MAT-treated groups were signifi- cantly （ P 〈 0.05 ）. Conclusion： Matrine could prevent and treat EAE rats and the mechanism maybe related to reduce the expression of TLR4 and MD-2 of rats.