Short communication: Subcellular motion compensation for minimally invasive microscopy, in vivo: evidence for oxygen gradients in resting muscle.
BACKGROUND
In vivo microscopy seeks to observe dynamic subcellular processes in a physiologically relevant context. A primary limitation of optical microscopy in vivo is tissue motion, which prevents physiological time course observations or image averaging.


OBJECTIVE
To develop and demonstrate motion compensation methods that can automatically track image planes within biological tissues, including the tissue displacements associated with large changes in blood flow, and to evaluate the effect of global hypoxia on the regional kinetics and steady state levels of mitochondrial NAD(P)H.


RESULTS
A dynamic optical microscope, with real-time prospective tracking and retrospective image processing, was used collect high-resolution images through cellular responses to various perturbations. The subcellular metabolic response to hypoxia was examined in vivo. Mitochondria closest to the capillaries were significantly more oxidized at rest (67+/-3%) than the intrafibrillar mitochondria (83+/-3%; P<0.0001) in the same cell.


CONCLUSIONS
These data are consistent with the hypothesis that a significant oxygen gradient from capillary to muscle core exists at rest, thereby reducing the oxidative load on the muscle cell.
Schroeder
James L
JL
Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute,/NIH,10 Center Drive, Bethesda, MD 20892, USA.
Luger-Hamer
Merav
M
Pursley
Randall
R
Pohida
Tom
T
Chefd'hotel
Chris
C
Kellman
Peter
P
Balaban
Robert S
RS
D000818:Animals; D016477:Artifacts; D002196:Capillaries / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism* / Q000503:physiopathology; D007700:Kinetics; D035002:Lower Extremity; D051379:Mice; D036641:Microscopy, Fluorescence, Multiphoton; D008931:Mitochondria, Muscle / Q000378:metabolism*; D009038:Motion; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism*; D009249:NADP / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D025341:Principal Component Analysis; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted
D009249:NADP; D010100:Oxygen