基于VEGF/VEGFR2信号通路探究苗药铁筷子醇提物抗类风湿关节炎大鼠滑膜血管新生作用

Probing the anti-rheumatoid arthritis synovial neovascularization of alcoholic extracts of the Miao medicinal plant helleborus thibetanus franchon in rats based on the VEGF/VEGFR2 signaling pathway

目的本项目拟以“苗药铁筷子”为研究对象,研究其对胶原诱导型(collagen-induced arthritis,CIA)大鼠抗炎活性及VEGF/VEGFR2/P38 MAPK通路的调控机制。方法将60只雌性Wistar大鼠,随机分为正常组、模型组、阳性药物组、铁筷子低、中、高剂量组,每组10只。将牛Ⅱ型胶原蛋白溶液注入大鼠尾部,复制大鼠模型,阳性药物组灌胃给予甲氨蝶呤(methotrexate,MTX)2.0 mg/(kg·d),每隔1 d 1次;铁筷子低、中、高3个剂量组以铁筷子醇提取物灌胃0.25、0.5和1 g/(kg·d),每天1次;正常组、模型组均采用等量NaCl溶液灌胃;连续灌胃28 d。治疗过程中,观察各组大鼠一般状况,记录体重变化,测定大鼠足底厚度;治疗结束后取大鼠后肢,经Micro-CT检测骨质破坏程度、苏木素-伊红(HE)染色法进行关节滑膜的病理学研究,免疫组织化学染色观察滑膜新生血管数量,反转录聚合酶链反应法(qRT-PCR)在大鼠滑膜组织中检测血管内皮生长因子(vascular endothelial growth factor,VEGF)-A、血管内皮细胞生长因子受体2(vascular endothelial growth factor receptor 2,VEGFR2)、肿瘤坏死因子(tumer necrosis factor,TNF)-α的mRNA水平,蛋白免疫印迹法(Western Blot)检测VEGF、VEGFR2、p-P38、p-AKT的表达,以探索苗药铁筷子治疗类风湿性关节炎的潜在作用机制。结果与正常组比较,模型组大鼠体重降低显著(P<0.01),足肿胀度明显增加(P<0.01),病理切片可见踝关节及后肢其他小关节滑膜组织明显增生、大量炎性细胞浸润,骨组织表面可见啃噬样病变,滑膜新生血管数量明显增多,Micro-CT显示明显骨质破坏、骨量百分比、骨小梁厚度、骨密度均显著下降,关节滑膜组织中VEGF-A、VEGFR2、TNF-αmRNA水平显著升高(P<0.01),VEGF-A、VEGFR2、p-P38、p-AKT蛋白表达量均显著升高(P<0.01)。与模型组比较,铁筷子醇提物呈剂量依赖性改善上述情况,以铁筷子高剂量组效果最优,大鼠的体重显著升高(P<0.05),足肿胀度明显下降(P<0.05),滑膜组织病理学损伤及骨组织啃噬样病变情况明显好转,滑膜组织新生血管明显减少,VEGF-A、VEGFR2、TNF-αmRNA水平明显降低(P<0.01),VEGF-A、VEGFR2、p-P38、p-AKT蛋白表达量显著降低(P<0.01)。结论苗药铁筷子可能通过调节VEGF/VEGFR2信号通路减轻CIA大鼠关节炎性损伤,进而发挥治疗类风湿关节炎的作用。

Objective This project aimed to study the Miao medicine helleborus thibetanus franchon,including investigating its anti-inflammatory activity in collagen-induced arthritis CIA rats and its mechanism of VEGF/VEGFR2/P38 MAPK pathway regulation.Methods Sixty female Wistar rats were randomly divided into six groups:normal;model;positive drug;and low,medium,high dose groups,with 10 rats in each group.Bovine typeⅡcollagen solution was injected into the tail of rats to construct the rheumatoid arthritis model,and the positive drug group was given MTX2.0 mg/(kg·d)by gavage once every other day.The three groups of helleborus thibetanus franchon low,medium,and high dose were gavaged with helleborus thibetanus franchon ethanol extract at 0.25,0.5 and 1 g/(kg·d)once a day.The normal and model groups were given an equivalent volume of NaCl solution,with continuous administration lasting for 28 days.During treatment,the general condition of the rats was observed,body weight changes recorded,and foot thickness measured.After treatment and euthanasia,the rats’hind limbs were removed for Micro-CT to detect bone destruction;hematoxylin and eosin staining for pathological investigattion of the synovial membrane;immunohistochemistry to observe neovascularization in the synovium;quantitative reverse-transcription PCR to detect mRNA levels of VEGF-A,VEGFR2,TNF-αin the synovial tissue;and Western Blot to detect the expression of VEGF,VEGFR2,p-P38,p-AKT.The analyses were used to explore the potential mechanisms of action of the Miao medicine helleborus thibetanus franchon in treating rheumatoid arthritis.Results Compared with the normal group,the model group showed significant weight loss(P<0.01),increased foot swelling(P<0.01),visible proliferative synovial tissue with inflammatory cell infiltration,erosive lesions on bone surfaces,increased neovascularization in the synovium,and significant bone destruction in Micro-CT,with reduced bone percentage,trabecular thickness,and bone density.The levels of VEGF-A,VEGFR2,TNF-αmRNA and VEGF-A,VEGFR2,p-P38,p-AKT proteins were significantly elevated(P<0.01).Compared with the model group,the helleborus thibetanus franchon ethanol extract-treated groups showed improvements in these conditions in a dose-dependent manner,with the high-dose group receiving the best effect.There was a significant increase in the rats’body weight(P<0.05);reduction in foot swelling(P<0.05);amelioration of synovial and erosive bone lesions;reduction in neovascularization in the synovium;and significantly lower levels of VEGF-A,VEGFR2,and TNF-αmRNA,and VEGF-A,VEGFR2,p-P38,and p-AKT protein(P<0.01).Conclusions The Miao medicine plant helleborus thibetanus franchon may alleviate joint inflammatory damage in CIA rats by modulating the VEGF/VEGFR2 signaling pathway,thereby exerting therapeutic effects on rheumatoid arthritis.