title: Wavelength-dependent backscattering measurements for quantitative monitoring of apoptosis, part 2: early spectral changes during apoptosis are linked to apoptotic volume decrease.
abstract: Elastic scattering spectroscopy (ESS), in the form of wavelength-dependent backscattering measurements, can be used to monitor apoptosis in cell cultures. Early changes in backscattering upon apoptosis induction are characterized by an overall decrease in spectral slope and begin as early as 10 to 15 min post-treatment, progressing over the next 6 to 8 h. The timescale of early scattering changes is consistent with reports of the onset of apoptotic volume decrease (AVD). Modeling cellular scattering with a fixed distribution of sizes and a decreasing index ratio, as well as an increased contribution of the whole cell to cellular scattering, resulting from increased cytoplasmic density, is also consistent with observed spectral changes. Changes in ESS signal from cells undergoing osmotically-induced volume decrease in the absence of apoptosis were similar, but smaller in magnitude, to those of apoptotic cells. Further, blockage of Cl(-) channels, which blocks AVD and delays apoptosis, blocked the early scattering changes, indicating that the early scattering changes during apoptosis result, at least partially, from AVD. Work continues to identify the additional sources of early spectral scattering changes that result from apoptosis induction.
authors: Boston University, Department of Biomedical Engineering, Boston, Massachusetts 02215, USA. cmulvey@bu.edu
authors: Christine S
authors: CS
authors: Mulvey
authors: Kexiong
authors: K
authors: Zhang
authors: Wei-Han
authors: WH
authors: Bobby Liu
authors: David J
authors: DJ
authors: Waxman
authors: Irving J
authors: IJ
authors: Bigio
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D048430:Cell Shape / Q000187:drug effects / Q000502:physiology; D048429:Cell Size / Q000187:drug effects; D005336:Fiber Optic Technology; D008027:Light; D008353:Mannitol / Q000494:pharmacology; D008954:Models, Biological; D015388:Organelles / Q000737:chemistry; D010316:Particle Size; D012542:Scattering, Radiation; D013057:Spectrum Analysis / Q000379:methods*; D019311:Staurosporine / Q000494:pharmacology
chemical_list: D008353:Mannitol; D053148:Caspase 3; D053179:Caspase 7; D019311:Staurosporine; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid