硝喹(Nitroquine)阻断鸡疟原虫孢子增殖机制的研究

感染鸡疟原虫的白洛克鸡,灌服硝喹2mg/kg3小时后,其血内配子体虽仍能在白纹伊蚊体内发育成动合子,但95%以上的动合子不能穿过围食膜,最后死于胃腔内。那些幸而能移行到胃壁基底层并形成卵囊者,不能进行DNA复制,其DNA量始终停留在正常48小时卵囊的水平。最后卵囊变性,或被吸收,仅留下疟色素,或变为黑孢子。

STUDIES ON THE MECHANISM OF SPORONTOCIDAL EFFECT OF NITROQUINE (CI-679) ON P. GALLINACEUM

One chick, weighing 1 kg, was inoculated intraveneously with the erythrocytic stages of P. gallinaceum. When the parasitemia reached approximately 40%, a batch of Aedes albopictus, as a control group was fed on the chick. After that, a single dose of Nitroquine (2mg/kg) was given orally to the same chick. 3 hours later, another batch of mosquitoes, as a test group, was fed on again.The samples for ookinete were stained with Giemsa-colophonium method and that for oocyst stained with both Giemsa and Feulgen's methods. The findings are as follows:The average number of ookinetes per midgut in the test group at 24th hour after blood meal was 958.6, that of oocysts at 6th day after infection was 32.7, only accounting for 3.3% of ookinetes. 34 and 48 hours after blood meal, there were a great number of ookinetes adhering to the peritrophic membrane both in the test and control groups. At the same time, 90% ookinetes free in the midgut cavity in the test group appeared shrunk and stiff, the nuclei condensed and black in colour; the cytoplasm dark grayish. However, the majority of that adhering to the peritrophic membrane seemed to be normal in appearence. On the contrary, in the control group there was no visible abnormal change and the average number of oocysts was 361.9 or 65.1% of ookinetes.One of the marked features of the oocysts in the test group was that the quantity of DNA in the course of development was never larger than that of 48 hours oocyst in the control group.All the findings indicate that the sporontocidal effect of Nitroquine may be chiefly to make the ookinetes hard to pass through the peritrophic membrane and to interfere with the reproduction of DNA in oocysts.