Studies
of bioluminescence in living animals, such as cell-based biosensor applications,
require measurement of light at different wavelengths, but accurate light
measurement is impeded by absorption by tissues at wavelengths <600 nm.
We present a novel approach to this problem—the use of
a plastic window in the skin/body wall of mice—that permits
measurements of light produced by bioluminescent cells transplanted into the
kidney. The cells coexpressed firefly luciferase (FLuc), a vasopressin receptor—
Renilla luciferase (RLuc) fusion protein, and a GFP
2-

-arrestin2 fusion protein. Following
coadministration of two luciferase substrates, native coelenterazine and luciferin, bioluminescence
is measured via the window using fiber optics and a
photon counter. Light emission from the two different luciferases, FLuc
and RLuc, is readily distinguishable using appropriate optical filters. When
coelenterazine 400a is administered, bioluminescence resonance energy transfer (BRET) occurs
between the RLuc and GFP
2 fusion proteins and is detected
by the use of suitable filters. Following intraperitoneal injection of
vasopressin, there is a marked increase in BRET. When rapid
and accurate measurement of light from internal organs is required,
rather than spatial imaging of bioluminescence, the combination of skin/body
wall window and fiber optic light measurement will be advantageous.
©2007
Society of Photo-Optical Instrumentation Engineers