Assessment of cyclobutane pyrimidine dimers by digital photography in human skin

• Published in: Journal of immunological methods 2011-10, Vol.373 (1-2), p.240-246
• Main Authors: ten Berge, Onno, van Velsen, Sara G.A., Giovannone, Barbara, Bruijnzeel-Koomen, Carla A.F.M., Knol, Edward F., Guikers, Kees, van Weelden, Huib
• Format: Article
• Language: English
• Subjects: Adult; Assessment; Biological and medical sciences; carcinogenesis; Cell Nucleus - genetics; Cell Nucleus - metabolism; digital images; DNA; DNA - genetics; DNA - metabolism; DNA Damage; DNA damage repair; DNA Repair; Dose-Response Relationship, Radiation; Epidermis - chemistry; Epidermis - metabolism; Epidermis - radiation effects; Female; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunohistochemistry; irradiation; keratinocytes; Linear Models; methodology; Molecular immunology; Photography - methods; Pyrimidine Dimers - analysis; Reproducibility of Results; Skin - chemistry; Skin - metabolism; Skin - radiation effects; Techniques; thymine; Thymine dimer; Time Factors; Ultraviolet Rays; UVB; Young Adult
• ISSN: 0022-1759; 1872-7905
• DOI: 10.1016/j.jim.2011.07.014

UV-mediated DNA damage and repair are important mechanisms in research on UV-induced carcinogenesis. UV-induced DNA-damage and repair can be determined by immunohistochemical staining of photoproduct positive nuclei of keratinocytes in the epidermis. We developed a new method of analysing and quantifying thymine dimer (TT-CPD) positive cells in the epidermis. Normal skin of healthy controls was exposed to UVB ex vivo and in vivo. Skin samples were immunohistochemically stained for TT-CPDs. Digital images of the epidermis were quantified for TT-CPDs both visually and digitally. There was a UVB-dose dependent induction of TT-CPDs present in the ex vivo UVB-irradiated skin samples. The linear measurement range of the digital quantification was increased compared to the manual counting. The average 24-hour repair rate of the initiated TT-CPDs elicited by the UVB irradiation at T=0 of the 8 HCs showed a 34% decrease of TT-CPD photoproducts by the manual counting method and a 51% decrease determined by digital counting. The digital quantification method improves immunohistochemical quantification of DNA photo damage. It is more sensitive in measuring the extent of DNA-damage per nucleus. ► The quantification of DNA damage is important in (skin) carcinogenesis research. ► Immunohistochemical quantification offers topographical advantages. ► A new method was therefore developed.