Bacterial 16S rRNA genes and expression of IL-1β, TNF-α and IgA in prostate tissues

Abstract

To investigate the role of bacteria in the etiology of chronic prostatitis. Complete prostate specimens were obtained at autopsy from 192 organ donors (aged 20 - 38 years old) during 2002 to 2008 who died of non-prostatic diseases. One tissue taken from the peripheral prostatic zone according to McNeal was divided into two pieces. One piece of tissue was taken for routine pathological examinations and immunohistochemical studies of interleukin (IL)-1β, tumor necrosis factor-α (TNF-α) and IgA. Another one was taken for PCR assay to detect the bacterial 16S rRNA genes (16S rDNA). Of 192 prostate specimens, 64 (33.3%) had pathological changes of chronic prostatitis and 38 (19.8%) specimens was positive for bacterial 16S rDNA. Positive rates of 16S rDNA in chronic prostatitis and non-prostatitis specimens were 50.0% (32/64) and 4.6% (6/128) respectively (χ(2) = 55.185, P < 0.001). Expressions of IL-1β, TNF-α and IgA in specimens of chronic prostatitis were significantly higher than those in non-prostatitis specimens (P < 0.001). A positive correlation could be found among three immunohistochemical indicators (P < 0.01). In 64 specimens with chronic prostatitis, a significant expression of IL-1β, TNF-α and IgA was more often demonstrated in 16S rDNA positive group than in 16S rDNA negative group (P < 0.001). The up-regulations of bacterial 16S rDNA, cytokines and immunoglobulin A are involved in inflammatory response of chronic prostatitis. Bacterial infection may be an important cause of chronic prostatitis.