Premium
Lymphatic Endothelial Cell Response to X‐Ray Irradiation
Author(s) -
Narayanan Anand,
Ford John,
Zawieja David
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.726.10
Subject(s) - lymphatic system , medicine , viability assay , pathology , radiation therapy , lymphedema , irradiation , lymphangiogenesis , nuclear medicine , cell , chemistry , cancer , metastasis , biochemistry , physics , breast cancer , nuclear physics
The lymphatics play a key role in the redistribution of interstitial fluids, cytokines, and immune cells via lymph formation. Severe impairment in lymphatic function causes swelling and inflammation, diagnosed as lymphedema. Secondary lymphedema is a known side effect cancer patients experience after radiation therapy; however, the pathogenesis is unknown. Furthermore astronauts develop edema while in space, being exposed to chronic, low‐dose, high LET background radiation. The lymphatics response radiation has not been extensively investigated. This is one of the first investigations characterizing lymphatic endothelium responses to radiation via viability and cell morphological measures. METHODS Primary, rat mesenteric lymphatic endothelial cells were exposed to a broad range of X‐ray (250 kVp, ~0.75 Gy/min) doses: 0, 0.5, 1, 1.5, 2, 4, 16 Gy, and travel sham. Cell viability was analyzed by XTT viability kit between 6–268 hours post‐irradiation at multiple time points. 24 and 72‐hours post‐irradiation, immunofluorescence was performed for β‐catenin, F‐actin, VE‐cadherin, DRAQ7, and measured by confocal microscopy (20× + 63× average z‐stack projections, 0.5 μm slices). No measurable differences were seen between travel sham and 0 Gy; therefore, statistical comparisons of treatment groups were made with 0 Gy group by 1‐way ANOVA and nonparametric Wilcoxon test ( p<0.05) . RESULTS Cell viability dropped in > 1 Gy groups at day 3, but became comparable to 0 Gy values after day 7. Cell morphometry showed radiation sensitivity at all doses. Notably there was a loss of cell‐to‐cell adhesion with irradiated cells increasing in surface area coverage, marked reduction in nuclei per equivalent field of view, and increased cellular roundness. This was coupled with decreased β‐catenin & VE‐cadherin intensity and altered F‐actin anisotropy leading to a loss of intercellular contact. CONCLUSIONS Lymphatics show radiation sensitivity in the context of these cell culture experiments. Our results may have functional implications of lymphatics in tissue, with potential endothelial barrier dysfunction leading to leakage and edema. These preliminary experiments will build the framework for future investigations towards clinical and space‐flight relevant lymphatic radiation exposure response. Support or Funding Information AN is supported by the NASA‐National Space Biomedical Research Institute Predoctoral Fellowship through NCC 9–58.