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Journal of Biomedical Optics • Open Access

Ex vivo optical metabolic measurements from cultured tissue reflect in vivo tissue status
Author(s): Alex J. Walsh; Kristin M. Poole; Craig L. Duvall; Melissa C. Skala

Paper Abstract

Optical measurements of metabolism are ideally acquired in vivo; however, intravital measurements are often impractical. Accurate ex vivo assessments would greatly broaden the applicability of optical measurements of metabolism. We investigate the use of live tissue culture experiments to serve as a surrogate for in vivo metabolic measurements. To validate this approach, NADH and FAD fluorescence intensity and lifetime images were acquired with a two-photon microscope from hamster cheek pouch epithelia in vivo, from biopsies maintained in live tissue culture up to 48 h, and from flash-frozen and thawed biopsies. We found that the optical redox ratio (fluorescence intensity of NADH/FAD) of the cultured biopsy was statistically identical to the in vivo measurement until 24 h, while the redox ratio of the frozen-thawed samples decreased by 15% (<b<p<0.01</b<). The NADH mean fluorescence lifetime (τm) remained unchanged (<b<p<0.05</b<) during the first 8 h of tissue culture, while the NADHτm of frozen-thawed samples increased by 13% (<b<p<0.001</b<). Cellular morphology did not significantly change between in vivo, cultured, and frozen-thawed tissues (<b<p<0.05</b<). All results were consistent across multiple depth layers in this stratified squamous epithelial tissue. Histological markers for proliferation and apoptosis also confirm the viability of tissues maintained in culture. This study suggests that short-term ex vivo tissue culture may be more appropriate than frozen-thawed tissue for optical metabolic and morphologic measurements that approximate in vivo status.

Paper Details

Date Published: 1 November 2012
PDF: 8 pages
J. Biomed. Opt. 17(11) 116015 doi: 10.1117/1.JBO.17.11.116015
Published in: Journal of Biomedical Optics Volume 17, Issue 11
Show Author Affiliations
Alex J. Walsh, Vanderbilt Univ. (United States)
Kristin M. Poole, Vanderbilt Univ. (United States)
Craig L. Duvall, Vanderbilt Univ. (United States)
Melissa C. Skala, Vanderbilt Univ. (United States)


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