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Ultrastructural modifications during the metabolism of metronidazole by Trypanosoma cruzi
Abstract:
Trypanosoma cruzi epimastigotes incubated in the presence of [14C] metronidazole are capable of a rapid uptake of the drug as shown by timecourse experiments and by autoradiography of the cells. The drug is metabolized to a more polar compound which has the chromatographic behavior of 2-methyl-5-nitroimidazole-1-yl-acetic acid. Mass spectral analysis of the metabolite shows diagnostic mass values (185, 184, 126) which are compatible with the 2-methyl-5-nitroimidazole-1-yl-acetic acid derivative. Flavone dramatically increases the production of the metabolite both in control and cells pretreated with phenobarbital. The cells show the presence of vesicles whose number is not significantly increased by phenobarbital. Metronidazole, on the other hand, significantly increases the number of vesicles in both control and cells grown in phenobarbital. The vesicles do not contain acid phosphatase and/or polyphosphates. It is concluded that the vesicles may correspond to a marked proliferation of the endoplasmic reticulum. A secondary effect of flavone is the proliferation of the mitochondrial membranes.
Insights
Trypanosoma cruzi rapidly absorbs and metabolizes metronidazole, forming a unique acetic acid derivative. Flavone enhances this drug metabolism, while metronidazole itself induces cellular vesicle formation, likely endoplasmic reticulum proliferation.
Area of Science:
- Parasitology
- Biochemistry
- Cell Biology
Background:
- Trypanosoma cruzi is the causative agent of Chagas disease.
- Metronidazole is an antimicrobial drug with activity against anaerobic protozoa.
- Understanding drug uptake and metabolism in parasites is crucial for developing new therapies.
Purpose of the Study:
- To investigate the uptake and metabolism of metronidazole in Trypanosoma cruzi epimastigotes.
- To identify the metabolic products of metronidazole.
- To explore the effects of flavone and phenobarbital on metronidazole metabolism and cellular structures.
Main Methods:
- Time-course experiments and autoradiography to study drug uptake.
- Chromatography and mass spectrometry to identify metabolites.
- Electron microscopy to observe cellular changes, including vesicle formation.
Main Results:
- Trypanosoma cruzi epimastigotes rapidly uptake [14C] metronidazole.
- Metronidazole is metabolized to 2-methyl-5-nitroimidazole-1-yl-acetic acid.
- Flavone significantly increases metabolite production.
- Metronidazole induces vesicle formation, potentially indicating endoplasmic reticulum proliferation.
- Flavone also causes proliferation of mitochondrial membranes.
Conclusions:
- Trypanosoma cruzi actively metabolizes metronidazole.
- Flavone acts as a potent enhancer of this metabolic pathway.
- Metronidazole induces significant ultrastructural changes in the parasite, characterized by vesicle proliferation.
- These findings provide insights into the interaction of T. cruzi with metronidazole and potential drug resistance mechanisms.