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Colcemid alters s phase and other parameters in skin during chronic exposure to benzo(a)pyrene
Author(s) -
Miller Marian L.,
Andringa Anastasia,
Albert Roy E.,
Cody Terence
Publication year - 1996
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/(sici)1097-0029(19961101)35:4<307::aid-jemt1>3.0.co;2-j
Subject(s) - colcemid , mitotic index , mitosis , chemistry , microbiology and biotechnology , andrology , keratinocyte , pharmacology , biology , medicine , biochemistry , in vitro
Abstract The administration of Colcemid for collecting mitotic figures in a carcinogenesis study, using benzo(a)pyrene (BaP), diminished the experimental differences between exposed and control mice. A dose‐related increase in noncollected mitotic index (n‐mitotic index) was seen in keratinocytes in the dorsal epidermis of mice which received four weekly treatments of BaP at 16, 32 and 64 μg in 50 μl of acetone. In contrast, the number of mitotic figures collected for 4 hr by Colcemid block (c‐mitotic index) was depressed at 16 μg, unchanged at 32 μg, and elevated at 64 μg of BaP. Weekly treatments with 4, 8 or 16 μg BaP for 3–8 months induced an elevation in both n‐mitotic and c‐mitotic indices. The differences in results produced by the two methods of determining mitotic index depended upon dose and duration of treatment with BaP. The administration of Colcemid to acetone‐treated mice increased the labeling index (number of labeled cells) and reduced the rate of DNA synthesis (low grain count per keratinocyte nucleus). After chronic application of BaP, Colcemid abrogated the increase in labeling index, but produced no additional effect on the number of grains per labeled keratinocyte. The modifying effect of Colcemid was greatest when administered during the peak of the tissue response to BaP. A number of significant changes in morphology of the skin associated with chronic exposure to BaP were attenuated by the use of Colcemid. © 1996 Wiley‐Liss, Inc.