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目的研究甲醛对SD大鼠胚胎心脏发育的毒性作用。方法选择成功受孕的20只成年健康SD雌鼠,随机平分为4组。各组大鼠均从孕第7天开始每日上午9∶00吸入不同浓度甲醛进行染毒,每日2 h,连续染毒12 d,建立染毒模型。待各组孕鼠自然分娩后,检测新生仔鼠胚胎发育的一般毒性及心脏毒性,同时观察心脏的病理学。结果第4组仔鼠平均出生体重分别与第1、2、3组两两比较,差异均有统计学意义(P<0.05)。心脏畸形有4只,均在第4组,主要心脏畸形表现为室间隔缺损(VSD)。第1、2、3组致畸率均为0.00%,第4组致畸率为11.76%。第4组和第1、2、3组仔鼠血清AST水平分别两两比较,差异均有统计学意义(P<0.05)。第3组和第1、2组仔鼠血清AST水平分别两两比较,差异均有统计学意义(P<0.05)。第4组仔鼠电镜下可见心肌组织肌原纤维排列紊乱;线粒体肿大,大小不等,嵴断裂、溶解,有较多空泡形成;线粒体间糖原颗粒少。第4组仔鼠心脏有明显变性水肿,细胞胞浆内有颗粒样物质,个别细胞可见核浓缩、核碎裂等细胞坏死表现,心肌细胞横纹不清。结论高水平甲醛具有胚胎毒性,可降低平均胎产数及仔鼠出生体重,导致小鼠胚胎心脏受损,发生先天性心脏病的可能性大。
Objective To study the toxic effects of formaldehyde on embryonic heart development in SD rats. Methods Twenty healthy female SD rats were selected and divided into 4 groups randomly. Rats in each group were exposed to different concentrations of formaldehyde at 9:00 am every day from the 7th day of pregnancy. The rats were exposed to different concentrations of formaldehyde for 2 days every day for 12 days to establish models of exposure. After each group of pregnant mice were given natural childbirth, the general toxicity and cardiotoxicity of embryos of newborn offspring were tested, and the pathology of the heart was also observed. Results The average birth weight of pups in group 4 was significantly higher than that in groups 1, 2 and 3, respectively (all P <0.05). There were 4 heart malformations, all in group 4, with major cardiac malformations presenting as ventricular septal defect (VSD). The teratogenic rates of group 1, group 2 and group 3 were both 0.00% and the teratogenic rates of group 4 were 11.76%. Serum AST levels in group 4 and groups 1, 2, and 3 were statistically significant (P <0.05), respectively. Serum AST levels in group 3 and groups 1 and 2 were statistically significant (P <0.05). Electron microscopy showed that myocardial myofibrils were disordered in the fourth group. The mitochondria were enlarged, the size was not the same, the cristae were broken and dissolved, and more vacuoles were formed. There were less mitochondrial glycogen particles. Group 4 pups cardiac degeneration and edema, cytoplasm within the particle-like material, the individual cells can be seen nuclear condensation, nuclear fragmentation and other cell necrosis performance, cardiac cells horizontal stripes unclear. Conclusions High levels of formaldehyde have embryotoxicity, which can reduce the average number of fetal births and the birth weight of offspring. As a result, the embryonic heart is damaged and the possibility of congenital heart disease is high.