Mouse model for acute bacterial prostatitis in genetically distinct inbred strains.

OBJECTIVES: Prostatitis is a common urologic disease seen in adult men. As many as 50% of men will experience an episode of prostatitis in their lifetime, and 2% to 3% of men will have bacterial prostatitis. Because the pathogenic mechanisms of prostatitis remain unclear, we developed a reproducible mouse model of bacterial prostatitis in which to study the etiology and host factors associated with infection susceptibility.
METHODS: Male BALB/c, C3H/HeJ, C3H/HeOuJ, C57BL/6J, and (BALB/c x C3H/HeJ)F1 mice 13 weeks old were inoculated intraurethrally with 2 x 10(6) or 2 x 10(8) Escherichia coli. Control mice were inoculated with phosphate-buffered saline. The animals were killed at 5 days after inoculation to assess the intensities of the bladder and prostate infections.
RESULTS: Significant bladder or prostate infections were not present in the BALB/c, C57BL/6J, or (BALB/c x C3H/HeJ)F1 mice at either inoculum dose. In contrast, both C3H/HeJ and C3H/HeOuJ mice developed high bladder infections and severe, acute prostatitis at both doses. Control mice infected with phosphate-buffered saline had no bladder or prostate infections. The P values were less than 0.01 for the comparison of bladder and prostate colony-forming units between C3H/HeJ or C3H/HeOuJ and BALB/c, C57BL/6J, or F1 mice.
CONCLUSIONS: The strain-dependent differences in susceptibility indicate that genetic factors may play a major role in the etiology of bacterial prostatitis. Because F1 mice did not develop significant bladder and prostate infections, similar to the BALB/c parents, it appears that infection susceptibility is a recessive trait. The availability of this model will allow us to investigate the immunology, genetics, and histopathologic features of bacterial infection of the prostate.