Observation of mitochondrial morphology and biochemistry changes undergoing apoptosis by angularly resolved light scattering and cryoimaging

Mahsa Ranji; Dwight L. Jaggard; Britton Chance

doi:10.1117/12.646255

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24 February 2006 Observation of mitochondrial morphology and biochemistry changes undergoing apoptosis by angularly resolved light scattering and cryoimaging

Mahsa Ranji, Dwight L. Jaggard, Britton Chance

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Proceedings Volume 6087, Biophotonics and Immune Responses; 60870K (2006) https://doi.org/10.1117/12.646255
Event: SPIE BiOS, 2006, San Jose, California, United States

Abstract

Non-invasive optical techniques offer great potential for observation of mitochondrial metabolism and morphology alternations. Apoptosis can be a result of cancer therapy such as PDT* during which mitochondria are undergoing structural and biochemical changes with different time-courses. Angularly-resolved light scattering is a powerful optical method to study behavior of light interaction with cells and their internal structures. Mitochondria organelles of ~ 1μm size is of the scale for Mie scattering. Fluorescence imaging is another important diagnostic tool to monitor two important endogenous fluorophores of the mitochondrial matrix, NADH (Nicotinamide Adenine Dinucleotide) and FAD (Flavin Adenine Dinucleotide) as metabolic biomarkers. The normalized ratio of these fluorophores called the redox ratio (FP/FP+NADH)¹ is an indicator of metabolism status of tissue independent of the number of mitochondria. The FL5 cells are investigated in normal and apoptotic stages by light scattering, fluorescence imaging and electron microscopy. Apoptosis is induced by substrate withdrawal. Goniometry-based light scattering results, suggest an earlystage apoptosis (8h) causes shrinkage of mitochondria and condensation of cristae whereas a late-stage (24h) is related to swollen mitochondria. These results are consistent with electron microscopy images of mitochondria at the same times. These three techniques provide multiple correlated data: morphological, biochemical and histological changes. Each technique strengthens the hypothesis behind the other data and helps to depict the overall procession of events.

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Mahsa Ranji, Dwight L. Jaggard, and Britton Chance "Observation of mitochondrial morphology and biochemistry changes undergoing apoptosis by angularly resolved light scattering and cryoimaging", Proc. SPIE 6087, Biophotonics and Immune Responses, 60870K (24 February 2006); https://doi.org/10.1117/12.646255

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