Imaging immune response in breathing lung
SAN FRANCISCO – As with toddlers, tissues that are constantly in motion can be difficult to capture
in still images without at least a little blurring. But researchers have developed
a method of stabilization for living lung tissue that allows more precise imaging
without disrupting the organ’s normal function.
Neutrophils (green) are visualized
moving through alveolar capillaries marked with Texas Red dextran (red) under baseline
conditions. Images courtesy of E. Thornton and M. Looney, UCSF.
Thanks to the new method, the team was able for the first time
to observe both the real-time interaction of live cells in their natural habitat,
so to speak, and the sequence of events that makes up the immune response to lung
“We figured out a method for holding cells still enough
to image them without interrupting their normal processes,” said Max Krummel,
associate professor of pathology at the University of California. “This enabled
us to observe cellular events as they happen naturally rather than the usual way,
which is to stop the motion of cellular processes in order to photograph them.”
Lung cells marked in the Actin-CFP transgenic mouse (green) are stabilized with an imaging
window, and breathing artifacts are removed by averaging 15 video-rate frames.
In the technique, a custom rig device applies a gentle amount
of suction to the surface of the tissue, the suction holds the viewing region in
place within the range of the microscope, and then a two-photon microscope photographs
the tissue. The researchers took footage 30 times per second to reveal, for example,
which cells worked together in response to an injury. They used this information
to identify the functions of different cell types.
The team plans to work on miniaturizing the stabilizing rig to
provide imaging for live tissue biopsies. The research was published online Dec.
12, 2010, in Nature Methods (Vol. 8, pp. 91-96, 2011).
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