Water-avoidance stress aggravates prostatic inflammation in a murine model of chronic prostatitis.

Abstract

To date, few studies have considered the influence of psychological factors on chronic prostatitis (PRO) models. Here, we aimed to refine a murine PRO model combining chemically induced prostatitis with psychological stress. A total of 40 mice were randomly divided into four groups: normal control (NC) group, PRO group, water avoidance stress (WAS) group, and PRO + WAS group. Ten mice were assigned to each group: five for cystometrograms (CMGs) and five for von Frey testing and histological analysis. PRO was induced through a prostatic injection of 10% paraformaldehyde. The WAS mice were placed on the middle platform for 1 h per day for 10 consecutive days. The results of the von Frey test demonstrated that both WAS and PRO induced bladder hyperalgesia in mice, and the WAS + PRO group showed significant pelvic pain symptoms either. The CMG results suggested that the PRO group, the WAS group, and the PRO + WAS group all exhibited bladder overactivity, presented as a shortened micturition interval and decreased threshold pressure evoking bladder contraction. The symptoms of the PRO group and the PRO + WAS group were more severe than those of the WAS group. The tissue staining results indicated that WAS itself caused only mild prostatic inflammation but could significantly aggravate chemical-induced prostatic inflammation, as well as the total number of mast cells and proportion of activated mast cells. Our refined murine PRO model could manifest persistent bladder overactivity, pelvic hyperalgesia and prostatic inflammation. WAS could induce mild prostatic inflammation and aggravate primary prostatic inflammation.