The Effect Of Dihydroartemisinin On The Trophozoites Of Giardia Lamblia In Vitro

Aim: To investgate the effect of dihydroartemisinin(DHA) on the trophozoites of G lamblia in vitro. Methods: G lamblia cultivated axenically with modified TYI-S-33 medium were divided into three groups: dihydroartemisinin group (DHA group), metronidazole group (MTZ or positive control group) and control group. The trophozoites of DHA group were cultivated in six different drug concentrations (6.25μg/ml, 12.5μg/ml, 25μg/ml, 50μg/ml and 100μg/ml) with three culture tubes for each concentration. Those in the metronidazole group were cultivated in the medium with different concentration of metronidazole (32.5μg/ml, 65μg/ml, 125μg/ml, 250μg/ml and 500μg/ml). The control group were performed in the same experimental conditions without drug. The morphological changes and vitality of the trophozoites were observed under the light microscope. The medial lethal concentration (LC₅₀) and mortality of the drug-treated organisms were determined. The ultrastructures of the drug-treated trophozoites were observed under the transmission electronic microscope at different time intervals (2h, 4h, 8h ,12h and 24hs). The drug-treated organism stained by rhodanmine phalloidin (R415) were checked and analyzed by flowcytometry and observed with confocal microscope to determine the microfilaments change. The cell cycle of the trophozoites exposed to DHA were analyzed with flowcytometry after stained by propidium iodide (PI). Genomic DNAs of the trophozoites in DHA and control groups were prepared by phenol-chloroform extraction method. Four pairs of oligonucleotide primers specific for the PCR amplifications of the tim-gene, TopoII-gene, lamin-gene and β-giardin-gene from G lamblia were designed and synthesized. Only PCR products from dihydroartemmsinin and the control groups were purified, sequenced and analyzed. The general protein of the organisms were extracted,...