苯并芘的早期妊娠毒性及五味子提取物在胚胎损伤中的保护作用

目的:探讨苯并芘(BaP)的早期妊娠毒性机制及五味子提取物对妊娠前BaP暴露致早孕期大鼠胚胎损伤的防治作用。方法:将75只雌性SD大鼠随机分为5组:空白对照组、Bap模型组、五味子低剂量组、中剂量组、高剂量组,每组15只。每日晨起灌胃给药,Bap模型组予BaP 2 mg·kg^-1·d^-1,五味子低、中、高剂量组分别予五味子提取物40、200、1 000 mg·kg^-1·d^-1+BaP 2 mg·kg^-1·d^-1,空白对照组予相同体积的生理盐水。给药15d后制备孕鼠模型,于妊娠第9天处死孕鼠,观察胚胎情况,透射电镜观察胚胎超微结构变化;氧化损伤试剂盒检测大鼠胚胎组织中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性水平和丙二醛(MDA)含量;酶联免疫吸附测定(ELISA)检测大鼠胚胎组织8-羟脱氧鸟苷(8-OHdG)含量。结果:(1)大鼠一般情况及胚胎形态学比较:空白对照组及五味子干预组大鼠胚胎肉眼观无明显异常,透射电镜示胚胎超微结构未见明显异常;Bap模型组大鼠胚胎大小不一,表面可见异常出血斑块,电镜示超微结构异常,凋亡细胞增加,胚胎内细胞出现异常凋亡结构;(2)与空白对照组相比,Bap模型组大鼠胚胎中SOD、GSH-Px活性显著降低(P<0.05或P<0.01),MDA含量显著升高(P<0.01);五味子提取物治疗后,高、中、低组大鼠胚胎中SOD活性较模型组不同程度上升(P<0.01或P<0.05),高剂量组GSH-Px活性较BaP模型组上升(P<0.05),高剂量组MDA含量较BaP模型组下降(P<0.05)。(3)与空白对照组相比,Bap模型组大鼠胚胎中8-OHdG水平显著上升(P<0.01);五味子提取物治疗后,高、中剂量组大鼠胚胎中8-OHdG水平较BaP模型组不同程度下降(P<0.01或P<0.05)。结论:妊娠前BaP暴露可对早孕期大鼠产生胚胎毒性,诱导早孕期大鼠胚胎的氧化损伤、DNA损伤及凋亡,五味子提取物可通过抗氧化、抗DNA损伤及抑制凋亡来发挥对胚胎的保护作用。

Study on the Toxicity of BaP in Early Pregnancy and Protective Effect of Schisandra Chinensis in Embryo Damage

Objective：To study the effect of Benzoa]pyrene (BaP) on the early pregnancy and its mechanism, as well as the protective effect of Schisandra chinesis extrac (SCE) on the Bap-induced damage of early embryo. Methods: Female SD rats were randomly divided into 5 groups (15 rats/group): control group, model (BaP 2 mg·kg-1·d-1) group, low-dose SCE (BaP plus SCE 40 mg·kg-1·d-1) group, middle-dose SCE (BaP plus SCE 200 mg·kg-1·d-1) group and high-dose SCE (BaP plus SCE 1 000 mg·kg-1·d-1) group. After 15 days of treatment, those female rats were mated with normal male rats to get the pregnancy. On the ninth day of gestation, all female rats were sacrificed. The ultrastructural change of embryo was observed by transmission electron microscope. The levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) in the embryonic tissues were measured by the oxidant-injury testing Kits; the level of 8-hydroxy-2 deoxyguanosine (8-OhdG) was also measured by a ELISA Kit. Results: There were no obvious abnormalities on the surface and ultrastructure in the control group and three SCE groups. The embryos in the model group were of uneven size and abnormal blood stasis on surface and abnormal ultrastructure, as well as abnormal apoptosis. The levels of SOD, GSH-Px were significantly decreased in the model group when compared with the control group (P＜0.05 or P＜0.01), while the level of MDA was increased significantly (P＜0.01). The levels of SOD in three SCE groups were significantly increased when compared with the model group (P＜0.01 or P＜0.05). The level of GSH-Px was significantly increased, and the level of MDA decreased in the high-does SCE group when compared with the model group (both P＜0.05). Compared with the control group, the model group had significantly lower level of 8-OHdG (P＜0.01). Interestingly, the levels of MDA were significantly decreased in the high-dose and middle-does SCE groups when compared with the model group (P＜0.01 or P＜0.05). Conclusions: Benzo a] pyrene exposure before pregnancy has the embryonic toxicity in rats, including oxidative damage, DNA damage and inducted apoptosis. SCE play a protective role in the early embryo through antioxidant, anti-DNA damage and anti-apoptosis.