Antibacterial Effect of an Intraprostatic Zinc Injection in a Rat Model of Chronic Bacterial Prostatitis

Lee, Choong Bum; Lee, Yoon Bo; Lee, Seung Ju; Cho, Yong Hyun; Cho, Dae Haeng

Abstract

PURPOSE
High levels of prostatic zinc are associated with prostatic antimicrobial activity and are depressed in patients with chronic prostatitis. We investigated the inhibition of bacterial growth in the rat prostate with chronic prostatitis after an intraprostatic injection of zinc and compared the two different types of zinc delivery. MATERIALS AND MTHODS: Ninety male Wistar rats were used in the study. Experimental chronic bacterial prostatitis was induced by the instillation of a bacterial suspension (Escherichia coli 108/ml) into the prostatic urethra. The animals were followed-up for 4 weeks and then injected intraprostatically with either 0.2ml of a zinc liposome or a zinc solution (0.04M zinc sulfate). Animals were sacrificed 4, 6, and 8 weeks after the injection. The inhibition of inflammation and its consequences were analyzed both microbiologically and histologically. The prostatic zinc concentrations were measured by inductively coupled plasma atomic emission spectrometry.
RESULTS
The average infection rates and mean Log10cfu/g of the zinc-treated groups were significantly lower than the controls. The histopathology showed resolving prostatitis in the zinc-treated groups compared with the controls. The prostatic zinc levels were higher in the zinc-treated groups than in the controls 4 and 6 weeks after the zinc injection (p<0.05). However, the zinc liposome and zinc solution groups were found to be effectively identical.
CONCLUSIONS
An intraprostatic injection of zinc inhibited bacterial growth by increasing the zinc levels in the rat prostatitis model. These results suggest that a local application of zinc to the prostate presents a new treatment modality for chronic bacterial prostatitis at the point of its pathogenesis.