1,2,4-三氯苯对蚯蚓生长和表皮及肠道超微结构的影响

通过自然土壤法对蚯蚓进行1,2,4-TCB急性暴露实验,研究了不同剂量的1,2,4-TCB对蚯蚓存亡、生长和表皮及肠道粘膜上皮细胞超微结构的影响。结果表明:1,2,4-TCB对蚯蚓14d半致死浓度为890.295mg·L-1;暴露剂量和培养时间均对蚯蚓生长抑制率产生正相关显著影响,但交互作用不显著;暴露于50mg·kg-11,2,4-TCB时,蚯蚓表皮分泌细胞增多,角质层增厚或上角质层损伤,肠道粘膜上皮细胞凹陷形成一定的溃疡面或呈撕裂分散状,第14天时,上角质层和肠道粘膜上皮细胞损伤均有所恢复;当暴露浓度为400mg·kg-1时,蚯蚓的角质层明显增厚,表皮出现大量的分泌细胞,肠上皮组织呈一定程度的撕裂并少量脱落,第14天时角质层变薄,分泌细胞减少,上角质层破损加剧,肠上皮细胞撕裂严重并持续脱落。第14天电镜观察显示:暴露浓度为50mg·kg-1时,肠上皮细胞线粒体嵴不清晰或断裂,结构模糊;暴露浓度为400mg·L-1时,部分线粒体空泡化或内部有絮状沉淀,嵴变短甚至消失。

Effects of 1,2,4-trichlorobenzene on the Growth and Ultrastructure of the Skin and Intestinal Epithelium of Earthworm

The mortality,growth and ultrastructural changes of the intestinal epithelium in earthworms(Eisenia fetida) that were exposed to the soil with different doses of 1,2,4-TCB by acute exposure test were investigated.The results showed that the median lethal concentrations(LC50) of the earthworms exposed to 1,2,4-TCB was 890.295 mg·kg-1 for 14 days.1,2,4-TCB inhibited the growth of earthworms during the test,and the inhibition rates were positively correlated with exposure time and 1,2,4-TCB dosage.Both exposure time and 1,2,4-TCB dosage had significant effects to the inhibition rates,but there was no significant interaction between them.Epidermis secretory cells increased,thickened,epicuticle damaged,intestinal epithelial caved in and formed ulcer surfaces or lacerated when the earthworms were exposed to 50 mg·kg-1 1,2,4-TCB.After exposure for 14 days,the damage of epicuticle and intestinal epithelial recovered a bit.Thickened and secretory cells increased obviously,intestinal epithelial lacerated and shed when the earthworms were exposed to 400 mg·kg-1 1,2,4-TCB.Thinner and epidermis secretory cells became fewer,epicuticle damaged,intestinal epithelial lacerated and shed seriously in 14 days' exposure.The ultrastructure of intestinal epithelium in 14 days' exposure revealed that cristae of mitochondria was not clear or broken and mitochondria confused at 50 mg·kg-1 1,2,4-TCB;some mitochondria vacuoled or appeared flocculent precipitate,cristae shortened or even disappeared at 400 mg·kg-1 1,2,4-TCB.