Effects of alpha-dimethylamino-cyclohexoxyl-dimethyl gallium on ultrastructure of erythrocytic stage of Plasmodium berghei and P yoelii

The effects of alpha-dimethylamino-cyclohexoxyl-dimethyl gallium (DCDG), a new antimalarial drug developed in China, on the ultrastructure of murine malaria parasites in vivo was studied in comparison with those of chloroquine (CQ) and artemisinin (Art). All these 3 antimalarials were administered ig to mice at dosages of 1-3, 40-80, and 200-400 mg.kg-1 for DCDG, CQ, and Art respectively, based on a similar intensity of morphological changes in the parasites. Blood samples were collected for electron microscopy from 15 min to 48 h after medication. The results showed that DCDG killed the malaria parasites (both asexual and sexual forms) rapidly. The most prominent changes in DCDG-treated parasites were serious dilation of perinuclear space, endoplasmic reticulum, mitochondrion and some other vesicles or intermembranous spaces. These led to the formation of large autophagic vacuoles containing some membranous materials, which were subsequently extruded. Then the parasite cells became more concentrated, finally pyknotic and died. The mode of action was very different from that of CQ and Art.