Are mouse lens epithelial cells more sensitive to γ-irradiation than lymphocytes?

Kristina Bannik,Ulrike Kulka,Olena Klymenko,Michael Atkinson,Michael Rosemann,Sabine Hornhardt,Theresa Faus-Kessler,Claudia Dalke,Klaus-Rüdiger Trott,Maria Gomolka,Ute Rössler,Jochen Graw

doi:10.1007/s00411-012-0451-8

Abstract

In this pilot study we compared for the first time the radiation sensitivity of mouse lens epithelial cells (LECs) and mouse lymphocytes. We freshly prepared LECs and lymphocytes and irradiated them with γ-rays (137Cs; doses ranging from 0.25 to 2 Gy). DNA damage and repair were evaluated by alkaline comet assay and γH2AX foci assay. Using the comet assay, we observed a dose-dependent increase in DNA damage in both cell types. The faster formation of single- and double-strand breaks in LECs of C57BL/6 mice at doses below 1 Gy needs to be confirmed in other mouse strains. Immunofluorescence for γH2AX foci showed a higher degree of lesions in LECs from C57BL/6J mice compared to those of JF1 mice and to lymphocytes of both strains. Correspondingly, repair of DNA damage proceeded faster in LECs of C57BL/6J mice compared to LECs of JF1 mice and lymphocytes of both strains. It is obvious that the lymphocytes of both strains repaired DNA lesions more slowly than the corresponding LECs. In conclusion, our results demonstrate that LECs of C57Bl/6 mice show a steeper dose–response than lymphocytes in both types of experiments. It shows that both test systems are able to be used also at doses below 0.25 Gy. The observed difference in DNA repair between the LECs from C57BL/6J mice compared to the LECs from JF1 mice and to the lymphocytes of both strains warrants further experiments to identify the underlying molecular mechanisms.

Highlights

For a long time, it has been known that ionizing radiation causes opacification of the ocular lens, and the lens is usually considered as a radiation-sensitive tissue
This article is published with open access at Springerlink.com. In this pilot study we compared for the first time the radiation sensitivity of mouse lens epithelial cells (LECs) and mouse lymphocytes
Primary cultures of C57BL/6J mouse LECs are quite heterogeneous in size after 24 h; they become more homogenous within the first 72 h and began at that time to elongate (Fig. 1)

Summary

Introduction

It has been known that ionizing radiation causes opacification of the ocular lens (cataracts), and the lens is usually considered as a radiation-sensitive tissue (for a review see Ainsbury et al 2009). For. Radiat Environ Biophys (2013) 52:279–286 very high doses (11 Gy), the participation of DNA damage followed by the formation of reactive oxygen species, DNA adducts and chromosomal rearrangements have been described as causative (Wolf et al 2008; Pendergrass et al 2010). Radiat Environ Biophys (2013) 52:279–286 very high doses (11 Gy), the participation of DNA damage followed by the formation of reactive oxygen species, DNA adducts and chromosomal rearrangements have been described as causative (Wolf et al 2008; Pendergrass et al 2010) These doses remain relevant to the lens only in particular therapy schedules of head-and-neck cancers. At higher doses the variation of the genetic background is less important compared to the general and severe damaging effects of ionizing radiation

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Conclusion