不同寄主植物桑寄生水提物对斑马鱼胚胎心脏发育毒性及机制研究

目的 研究不同寄主植物桑寄生Taxilli Herba水提物对斑马鱼胚胎心脏发育毒性及其机制，为桑寄生用药安全提供理论依据。方法 以受精后6 h(6 h post fertilization，6 hpf)正常发育的斑马鱼胚胎为动物模型，将桑树Morus alba、柳树Salix babylonica、油茶Camellia oleifera、夹竹桃Nerium indicum、苦楝Melia azedarach和漆树Toxicodendron trichocarpum 6种寄主植物桑寄生水提物各设置低、中、高3个药物浓度，分别处理斑马鱼胚胎，检测72 hpf孵化仔鱼的心脏形态、心率、心包面积、静脉窦(sinus venosus，SV)和动脉球(bulbus arteriosus，BA)间距、超氧化物歧化酶(superoxide dismutase，SOD)和过氧化氢酶(catalase，CAT)活性、心肌细胞的凋亡情况以及氧化应激相关酶基因［SOD1、CAT、谷胱甘肽S-转移酶2(glutathione S-transferase 2，GSTP2)]、心脏发育相关基因GATA结合蛋白5(GATA binding protein 5，GATA5)、NK2同源框5(NK2 homeobox 5，NKX2.5)、肌球蛋白重链6(Myosin，heavy chain 6，MYH6)]及心肌细胞凋亡相关基因B淋巴细胞瘤-2(B-cell lymphoma-2，Bcl-2)、Bcl-2相关X蛋白(Bcl-2 associated X protein，Bax)]的表达水平。结果 与空白组比较，除桑树寄主桑寄生外，其他5种桑寄生水提物处理的斑马鱼胚胎均出现不同程度的心包水肿、心率降低、心包面积和SV-BA间距增大(P＜0.05、0.01)，SOD和CAT活性降低(P＜0.05、0.01)，SOD1、CAT、GSTP2、GATA5、NKX2.5、MYH6的表达表现出明显的上调或下调(P＜0.05、0.01)。夹竹桃、苦楝和漆树3种寄主桑寄生还观察到心肌细胞凋亡，Bcl-2表达和Bcl-2/Bax值明显降低(P＜0.05、0.01)。结论 桑寄生对斑马鱼胚胎心脏发育毒性具有明显的寄主相关性，除桑树寄主桑寄生外，其他5种寄主桑寄生均表现出不同程度的心脏发育毒性，寄主植物不同，毒性机制也不同。

Cardiac developmental toxicity and mechanism of aqueous extracts of Taxilli Herba from different hosts in zebrafish embryo

Objective To study the cardiac developmental toxicity and mechanism of aqueous extracts of Sangjisheng (Taxilli Herba) from different hosts in zebrafish embryo, and provide theoretical basis for drug safety of Taxilli Herba. Methods The normally developed zebrafish embryos at 6 h post fertilization (6 hpf) was used as the animal model. Zebrafish embryos were treated with low-, medium-, high-concentrations of aqueous extracts of Taxilli Herba from Morus alba (mulberry, THM), Salix babylonica (willow, THW), Camellia oleifera (THC), Nerium indicum (oleander, THO), Melia azedarach (neem, THN) and Toxicodendron trichocarpum (hoggum, THH). Then, heart morphology, heart rate, pericardial area, and sinus venosus-bulbus arteriosus (SV-BA) spacing length, activities of superoxide dismutase (SOD) and catalase (CAT), and cardiomyocytes apoptosis of zebrafish at 72 hpf were observed and measured. The expression levels of oxidative stress-related genes SOD1, CAT, glutathione S-transferase 2 (GSTP2)], cardiac development-related genes GATA binding protein 5(GATA5), NK2 homeobox 5(NKX2.5), myosin heavy chain 6 (MYH6)] and cardiomyocyte apoptosis-related genes B-cell lymphoma-2 (Bcl-2), Bcl-2-related X protein (Bax)] were detected. Results Compared with control group, except for the zebrafish of THM, the other five groups all presented pericardial edema, decreased heart rate, increased SV-BA in varying degrees (P < 0.05, 0.01), activities of SOD and CAT were all reduced (P < 0.05, 0.01), SOD1, CAT, GSTP2, GATA5 and NKX2.5 expression levels were significantly up-or down-regulated (P < 0.05, 0.01). Cardiomyocytes appeared apoptosis in the groups of THO, THN and THH, Bcl-2 expression and Bcl-2/Bax were also significantly decreased (P < 0.05, 0.01). Conclusion Cardiac developmental toxicity of Taxilli Herba to zebrafish embryos is obviously host-dependent. Except for THM, the others all show varying degrees of cardiac developmental toxicity. The toxicity mechanism is also dependent on the host plants.