镉对长江华溪蟹精子发生的影响

EFFECTS OF CADMIUM ON SPERMATOGENESIS IN FRESHWATER CRAB (SINOPOTAMON YANGTSEKIENSE)

分别于 1999年 3～ 5月和 10～ 12月 ,利用透射电镜方法 ,按 1 5 μg/g体重的剂量体腔注射Cd2 + 于长江华溪蟹 (Sinopotamonyangtsekiense)体内 ,在 10min至 2 4h之间的若干时间段取材 ,观察精子发生过程中不同发育阶段生殖细胞的变化。结果表明 :镉注射后 0 5h ,各级生精细胞就开始出现超微结构的变化 ,主要表现为线粒体肿胀与空泡化 ,高尔基体变形 ,内质网扩张和膜结构损伤等。其中线粒体损伤出现最早 ,是最易受损伤的一个敏感细胞器。

Reproduction of Crustaceana is a complex regulated process which can be affected in several ways by heavy metals and other pollutants. For the first time the effect of cadmium on the male germ cell of the freshwater crab ( Sinopotamon yangtsekiense ) was studied by the means of body cavity injection (Cd 2+ 1 5 μg/g boby weight) in this paper. The germ cell at the different developmental stages in the treated and control individuals had been observed by transmission electron microscopy (TEM) in order to determine whether cadmium might have a morphological effect on them during spermatogenesis. The same experiment had been done twice in the period of March to May and October to December in 1999. In the experiment, male crabs were brought from aquatic product market in Taiyuan and raised in laboratory for more than a week before treatment. The mature male crabs in middle size were chosen and injected Cd 2+ into the body cavity. The treated and control animals were dissected in different times (10 min, 0 5 h, 1 h, 2 h, 4 h, 24 h). The results showed that all kinds of observed cells had been changed ultrastructurally after 30 minutes of cadmium treatment except for spermagone, and that the longer of cadmium treatment was, the more seriously the cells had been changed in morphology. Spermagone had ultrastructural changes after two hours of cadmium treatment; and their cell membrane had been broken partly and nuclear membrane distorted and most mitochondria vacuolated after four hours of treatment. In primary spermatocyte and secondary spermatocyte, ultrastructural changes had been observed after 30 minutes of Cd 2+ treatment, and changes of organelle were distinct after one hour of Cd 2+ treatment. The damaged order of organelle of spermatocyte was: mitochondria and endoplasmic reticula firstly (30 min), nuclear membrane and nucleoli secondly (2 h), cell membrane and Golgi complex and lysosome lastly (24 h). In secondary spermatocyte order, mitochondria had been damaged firstly (0 5 h) and cell membrane and nuclear membrane and endoplasmic reticula secondly (1 h). Injected cadmium 30 minutes later, the cell membrane of spermoblast had been damaged and acrosome had been distorted and mitochondria had been shifted 4 hours later, i.e.injecting cadmium into the animals could cause all organoid of all sorts of male germ cells damaged shortly. Among five kinds of male germ cell, spermagone was the latest one to be damaged by cadmium. Golgi complex was the least to be damaged by cadmium, its ultrastructure had been observed normally in secondary spermatocyte Ⅱ and had been damaged slightly in primary spermatocyte Ⅰ after 24 hours of treatment. Cell membrane and mitochondria were affected earlier than other organelle. The changes of cell membrane and mitochondria were including cell membrance swelled seriously (eg. spermoblast) and disintegrated partly, mitochondria distorted and vacluolated and broken, some mitochondria contracted and turned smaller than normal ones, some mitochondria cristae disappeared. At first nucleus had been distorted and nuclear membrane had been expanded slightly, chromatin of primary spermatocyte had been condensated to cluster and chromatin of secondary spermatocyte had been turned free 4 hours later. Ribosome and nucleoli had been increased to three or five, and some of the latter had been shifted around nuclear membrane 2 hours later. Rough endoplasmica reticula (RER) had been vacuolated largely and turned into smooth endoplasmica reticula (SER) by disassemblying ribosome from RER, which led to the increase of SER and ribosome. There were more lysosome and vacuolus in cytoplasmic matrix and other organella had been damaged seriously twenty–four hours later. The results showed that male germ cells of the experimented animals could be damaged by injecting cadmium into their body cavity. The organella with membrane structure were easily damaged, such as mitochondria, nucleus, endoplasmica reticula and cell membrane. Among them mitochondria was damaged ea