Assessment of Drug Activities against Giardia Using Hyperspectral Raman Microscopy.

Area of Science:

• Biochemistry
• Cell Biology
• Microscopy

Background:

• Giardiasis remains a significant public health concern, necessitating novel therapeutic strategies.
• Understanding drug interactions at the cellular and molecular level is crucial for effective treatment and combating drug resistance.

Purpose of the Study:

• To investigate the structural and molecular changes in Giardia cells upon exposure to metronidazole (MTZ) and oseltamivir (OSM) using Raman microscopy.
• To compare the effects of different drugs and incubation times on Giardia cell structures.

Main Methods:

• Label-free Raman microscopy was employed to analyze structural modifications in Giardia cells.
• Confocal fluorescence microscopy was used to confirm drug incorporation and impact on cell membranes.

Main Results:

• Metronidazole (MTZ) induced extracellular vesicle release containing toxic iron intermediates and modified triple-bond moieties, with notable changes in heme protein environment and iron transformation.
• Oseltamivir (OSM) altered phenylalanine and lipid structures, demonstrating a more destructive impact on the plasma membrane and lipid rafts.
• Incubation time influenced vesicle content, with shorter exposures showing protein, glycogen, and phospholipid releases, while longer exposures revealed transformed iron complexes.

Conclusions:

• Raman microscopy offers a powerful tool for label-free, simultaneous monitoring of cellular and molecular changes during drug treatment.
• The study elucidates multifaceted mechanisms underlying giardiasis treatment and potential drug resistance, highlighting distinct cellular responses to MTZ and OSM.