We labeled S-phase cell in BBN induced bladder tumor of rat using anti-bromodeoxyuridine antibody. The thymidine analogue, bromodeoxyuridine (BrdU), was incorporated into DNA during the S-phase of the cell cycle with intraperitoneal injection of
BrdU
for in vivo labeling study. Anti-BrdU monoclonal antibody antibody can be detected by the immunohistochemical method.
Sequential epithelial changes (normal, simple hyperplasia, nodular or papillary hyperplasia, papilloma and superficial cell carcinoma-Ta, TIS) were observed in urinary bladder of rat in proportion to the duration of BBN administration.
The BrdU labeling index, S-Phase fraction, was determined by counting the number of BrdU labeled cells in the tissue section. The average labeling index obtained using this method in control, simple hyperplasia, nodular hyperplasia, papillary
hyperplasia, paplilloma and superficial bladder tumor was 4.5, 6.8, 15.3, 22.2, 36.8 and 46 respectively (P<0.05). And labeling index values were gradually increased with progression of bladder mucosal lesion and prolongation of duration of BBN
exposure
(P<0.01).
BrdU labeled cells were mainly noted in the basal cell layers in early stage and in whole layers with increased numbers of positive cells in late stage.
In summary, high labeling index of BrdU in bladder tumor suggests a more malignant potential and thus a poor prognosis based on the fact that mean labeling index progressively increased with tumorigenesis.
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