Belosevic M, Faubert G M, MacLean J D
Department of Zoology, University of Alberta, Edmonton, Canada.
Gut. 1989 Sep;30(9):1213-9. doi: 10.1136/gut.30.9.1213.
The sequence of changes in the activity of six disaccharidases in the small intestine of gerbils during primary and secondary G lamblia infections was examined. The primary G lamblia infection induced a transient reduction in disaccharidase activity which was related to the highest trophozoite burden in the small intestine. During the primary exposure, a 30% to 85% decrease in the activity of enzymes was observed on days 10 and 20 after infection. Secondary exposure of gerbils to G lamblia caused a sharp decrease in disaccharidase activity as early as 24 h after challenge. The reduction in the enzyme activity was not influenced by the size of the challenge inoculum and occurred even when there were no live trophozoites in the small intestine. Disaccharidase deficiency could also be induced by challenge with the soluble extract of the trophozoites. Multiple challenge administrations of G lamblia trophozoites to gerbils induced a persistent disaccharidase deficiency. The results indicate that disaccharidase deficiency associated with the primary G lamblia infection probably represents a direct effect of the parasite on the brush border of the small intestine. On the other hand, the observed disaccharidase deficiency in the secondary G lamblia infection appears to be induced by the local immune responses of the host.
研究了沙土鼠在原发性和继发性蓝氏贾第鞭毛虫感染期间小肠中六种双糖酶活性的变化顺序。原发性蓝氏贾第鞭毛虫感染导致双糖酶活性短暂降低，这与小肠中最高的滋养体负荷有关。在初次感染期间，感染后第10天和第20天观察到酶活性下降了30%至85%。沙土鼠再次接触蓝氏贾第鞭毛虫后，早在攻击后24小时双糖酶活性就急剧下降。酶活性的降低不受攻击接种量大小的影响，即使小肠中没有活的滋养体也会发生。用滋养体的可溶性提取物攻击也可诱导双糖酶缺乏。多次给沙土鼠接种蓝氏贾第鞭毛虫滋养体可导致持续性双糖酶缺乏。结果表明，与原发性蓝氏贾第鞭毛虫感染相关的双糖酶缺乏可能代表寄生虫对小肠刷状缘的直接作用。另一方面，在继发性蓝氏贾第鞭毛虫感染中观察到的双糖酶缺乏似乎是由宿主的局部免疫反应诱导的。
