title: Analysis of the Ki-67 index in the vaginal epithelium of castrated rats treated with tamoxifen.
abstract: OBJECTIVE
  Vaginal atrophy and breast cancer are common conditions in postmenopausal women and tamoxifen is the standard endocrine treatment for hormone-sensitive tumors. The present study aimed to assess the effect of tamoxifen on Ki-67 protein expression in the vaginal epithelium of castrated rats.
  
  
  METHODS
  Forty Wistar-Hannover adult, virgin, castrated rats were randomly divided into two groups, group I (control, n=20) and group II (tamoxifen, n=20), receiving 0.5 ml of propylene glycol and 250 µg of tamoxifen diluted in 0.5 ml of propylene glycol, respectively, daily by gavage for 30 days. On the 31st day, the rats were euthanized and their vaginas were removed and fixed in 10% buffered formalin for the immunohistochemical study of Ki-67 protein expression. Data were analyzed by the Levene and Student's t tests (p<0.05).
  
  
  RESULTS
  The mean index of Ki-67 expression in the rat vagina of groups I and II was 4.04±0.96 and 26.86±2.19, respectively (p<0.001).
  
  
  CONCLUSIONS
  According to the results of the present study, tamoxifen, at the dose and treatment length used, induced a significant increase in the cell proliferation of the vaginal mucosa in castrated rats, as evaluated by Ki-67 protein expression.
authors.affiliation: Departamento de Ginecologia, Universidade Federal do Piauí, Teresina, Brazil.
authors.forename: Afif Rieth
authors.initials: AR
authors.lastname: Nery-Aguiar
authors.affiliation: Departamento de Ginecologia, Universidade Federal do Piauí, Teresina, Brazil.
authors.forename: Yousef Qathaf
authors.initials: YQ
authors.lastname: Aguiar
authors.affiliation: Morphology, Teresina/, PI, Brazil.
authors.forename: Airton Mendes
authors.initials: AM
authors.lastname: Conde Júnior
authors.affiliation: Departamento de Estatísticas, Universidade de São Paulo, São Paulo/, SP, Brazil.
authors.forename: Airlane Pereira
authors.initials: AP
authors.lastname: Alencar
authors.affiliation: Departamento de Ginecologia, Universidade Federal do Piauí, Teresina, Brazil.
authors.forename: Cleciton Braga
authors.initials: CB
authors.lastname: Tavares
authors.affiliation: Departamento de Ginecologia, Universidade Federal do Piauí, Teresina, Brazil.
authors.forename: Pedro Vitor
authors.initials: PV
authors.lastname: Lopes-Costa
authors.affiliation: Departamento de Mastologia, Universidade Federal de São Paulo, São Paulo/, SP, Brazil.
authors.forename: Afonso Celso
authors.initials: AC
authors.lastname: Nazário
authors.affiliation: Departamento de Ginecologia, Universidade Federal do Piauí, Teresina, Brazil.
authors.forename: Benedito Borges
authors.initials: BB
authors.lastname: da Silva
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D005260:Female; D019394:Ki-67 Antigen / Q000378:metabolism*; D023421:Models, Animal; D011897:Random Allocation; D017208:Rats, Wistar; D020845:Selective Estrogen Receptor Modulators / Q000494:pharmacology*; D013629:Tamoxifen / Q000494:pharmacology*; D014621:Vagina / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology
chemical_list: D019394:Ki-67 Antigen; D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen