title: Novel and quantitative DNA dot-blotting method for assessment of in vivo proliferation.
abstract: Immunohistochemical assessment of 5-bromo-2-deoxyuridine (BrdU) in tissue sections is a widely used method to evaluate cell proliferation in vivo. However, this method requires time-consuming preparation of paraffin sections and laborious counting of BrdU-labeled nuclei on multiple sections. Here, we report the development of a rapid and reliable method to quantitate BrdU incorporation in intestinal and liver tissues using a dot-blot method. In vivo models of colon or liver proliferation were used to analyze the usefulness and reliability of this new method. Mice were killed after BrdU injection, and genomic DNA was isolated from the tissues, denatured, and dot-blotted onto a nitrocellulose membrane. The incorporated BrdU was detected with a BrdU monoclonal antibody, and the signal intensity was densitometrically quantified. Results were compared with BrdU index determined by conventional immunohistochemistry on the same tissue samples. The patterns of colonic BrdU incorporation during fasting and refeeding, measured by the dot-blotting method and the immunohistochemical method, were similar. The BrdU incorporation in the regenerating liver after partial hepatectomy, evaluated by these two different methods, showed a strong correlation (R(2) = 0.91, P < 0.01). In addition, the inhibition of colon proliferation by the phosphoinositol 3-kinase inhibitor wortmannin was demonstrated by this dot-blotting method. In conclusion, the dot-blotting technique described in this report provides an accurate, more efficient, and possibly more reliable method for the assessment of in vivo proliferation compared with conventional immunohistochemical determination of BrdU-labeling index.
authors.affiliation: Dept. of Surgery, Univ. of Texas Medical Branch, 301 Univ. Boulevard, Galveston, Texas 77555-0536, USA.
authors.forename: Junji
authors.initials: J
authors.lastname: Ueda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Saito
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Watanabe
authors.forename: B Mark
authors.initials: BM
authors.lastname: Evers
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal; D001973:Bromodeoxyuridine; D049109:Cell Proliferation / Q000187:drug effects; D003106:Colon / Q000166:cytology / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D003720:Densitometry; D006498:Hepatectomy; D015151:Immunoblotting / Q000379:methods* / Q000592:standards; D007150:Immunohistochemistry; D008099:Liver / Q000378:metabolism*; D008115:Liver Regeneration / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013997:Time Factors; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D000911:Antibodies, Monoclonal; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D004247:DNA; D001973:Bromodeoxyuridine; D000077191:Wortmannin