Intraprostatic Lymphocyte Profiles in Aged Wistar Rats With Estradiol Induced Prostate Inflammation

Abstract

We report LS phenotypes in aged Wistar rats (Charles Rivers, Wilmington, Massachusetts) with EPI. EPI was induced in 36 to 40-week-old male rats by castration with subcutaneous injections of 17beta-estradiol (0.25 mg/kg daily) plus dihydrotestosterone propionate (2.5 mg/kg daily) in sesame oil for 30 days. Controls were sham castrated, aged rats that were injected with sesame oil. Prostate, spleen and blood LSs in aged and young (10 to 12-week-old) rats were identified by flow cytometry in a cluster of differentiation system. All prostates in 6, 17beta-estradiol plus dihydrotestosterone propionate treated rats and in 3 of 7 controls (43%) showed inflammation foci. All studied LSs in Aged-SPIs and Aged-EPIs were similar. Blood LSs in Aged-SPIs, Aged-EPIs, Aged-NPIs and Youngs showed no differences. Levels of lymphocytes bearing the natural killer marker were decreased, and levels of total T and CD4(+) T cells were increased in prostates with age. Intraprostatic and splenic levels of CD4(+) natural killer T cells were down-regulated significantly in Aged-SPIs and Aged-EPIs compared to those in Aged-NPIs and Youngs. Levels of CD45RC(+)CD4(+)alphabetaTCR(+) T cells were decreased 2-fold in the spleen and up-regulated 2-fold in the prostate of Aged-SPIs and Aged-EPIs compared to those in Aged-NPIs and Youngs. Similar LS features in Aged-SPIs and Aged-EPIs may indicate that the EPI model is appropriate for studies of the immune aspects of prostate inflammation. Imbalance between suppressive CD4(+) natural killer T cells and autoreactive CD45RC(+)CD4(+)alphabetaTCR(+) T cells in Aged-SPIs and Aged-EPIs may suggest their role in prostate inflammation in this model.