锌对镉所致胚胎毒性的保护作用研究

实验用Ｗｉｓｔａｒ大鼠，分为正常组、低锌组、低锌染镉组、正常染镉组和染镉高锌保护组，分别饲养，其中三组在孕８和１０天注射镉（２．０ｍｇ／ｋｇ）。妊娠第２０天处死动物，取血，并剖腹检查孕鼠内脏和胎鼠畸形情况。研究发现：与正常对照组相比，单纯缺锌即可引起胎鼠的吸收率增高和畸形的发生；而染镉（２．０ｍｇ／ｋｇ）也可引起胎鼠的吸收胎和迟死胎显著增加，并可引起皮下水肿、卷尾等外观畸形。在孕期缺锌的同时，给予孕鼠２．０ｍｇ／ｋｇ体重的镉，孕鼠在整个孕期体重呈负增长，胚胎不能形成；如给予孕鼠高锌饲养（２２７ｍｇ／ｋｇ），胎鼠可得到较好的保护，其吸收胎、死胎率明显下降，存活率显著上升，且胎鼠体重、身长也与对照组相差无几。提示孕鼠缺锌可引发胎儿畸形，缺锌染镉加重胚胎毒作用，而高锌膳食能拮抗镉所造成的胚胎毒作用。

Effect of Zinc on Cadmium Induced Fetal Damage

The effect of different zinc level on cadmium (Cd)-induced fetal damage was studied in pregnant rats. Seventy Waster rats were divided into five groups: zinc 30 mg/kg diet, zinc deficiency (3.2 mg/kg), zinc deficiency with Cd 2.0 mg/kg, zinc 30 mg with Cd 2.0 mg and zinc 227 mg with Cd 2.0 mg. The pregnant rats were killed on the 20 th day of gestation. Blood samples were taken and all the fetuses were examined. The result showed that zinc deficiency could induce fetus absorption or malformation, which were increased significantly in zinc dificient plus Cd rats. Fetuses can be protected if high dose of zinc (227 mg/kg) is given. The occurrence of fetus absorption and malformation decreased and survival increased in compared with the nonsupplemented group. The results suggested that fetal malformations can be induced by zinc deficiency, and being worse when Cd is added. Zinc supplementation can offset to some extent the toxic effect of Cd.