Related Experiment Video
Updated: May 16, 2026
A Rat Model of Compound Acne
Published on: November 1, 2024
Chronic prostatic infection and inflammation by Propionibacterium acnes in a rat prostate infection model
Jan Olsson1, Johanna Bergh Drott, Lovisa Laurantzon
1Department of Clinical Microbiology, Virology, Umeå University, Umeå, Sweden. jan.olsson@climi.umu.se
Abstract:
Chronic inflammation in the prostate, seen as infiltration of inflammatory cells into the prostate gland in histological samples, affects approximately half the male population without indication of prostate disease, and is almost ubiquitous in patients diagnosed with benign prostate hyperplasia and cancer. Several studies have demonstrated the gram-positive bacterium Propionibacterium acnes to be frequently present in prostate tissue from men suffering from prostate disease. P. acnes has been shown to be associated with histological inflammation in human prostatectomy specimens, and also to induce strong inflammatory response in prostate-derived tissue culture models. The present paper describes a rat model for assessment of the pathogenic potential of P. acnes in prostate. Prostate glands of Sprague Dawley rats (n = 98) were exposed via an abdominal incision and live P. acnes or, in control rats, saline were injected into the ventral and dorso-lateral lobes. Rats were sacrificed 5 days, 3 weeks, 3 months and 6 months post infection, and prostate tissue was analyzed for bacterial content and histological inflammation. Rat sera were assessed for levels of CRP and anti-P. acnes IgG. Live P. acnes could be recovered from the dorso-lateral lobes up to 3 months post infection, while the ventral lobes were cleared from bacteria at that time. In samples up to 3 months post infection, the dorso-lateral lobes exhibited intense focal inflammation. CRP and IgG levels were elevated throughout the span of the experiment, and reached maximum levels 3 weeks and 3 months post infection, respectively. We show that P. acnes have the potential to cause chronic infection in previously healthy prostate, and that the infection has potential to cause chronic histological inflammation in the infected tissue. The high prevalence of P. acnes in human prostate tissue calls for resolution of pathogenic details. The present rat model suggests that complications such as chronic inflammation may be induced by P. acnes infection.
Insights
Propionibacterium acnes can cause chronic prostate inflammation in rats. This study developed a rat model to investigate P. acnes
Area of Science:
- Urology
- Microbiology
- Pathology
Background:
- Chronic prostate inflammation is common, affecting half the male population and nearly all with benign prostate hyperplasia or cancer.
- Propionibacterium acnes (P. acnes) is frequently found in prostate tissue of men with prostate disease and linked to inflammation.
Purpose of the Study:
- To establish and utilize a rat model for evaluating the pathogenic potential of P. acnes in the prostate.
- To assess the capacity of P. acnes to induce chronic infection and inflammation in healthy prostate tissue.
Main Methods:
- Sprague Dawley rats (n=98) underwent abdominal surgery for direct injection of live P. acnes or saline into prostate lobes.
- Prostate tissues were analyzed for bacterial presence and histological inflammation at multiple time points (5 days to 6 months).
- Rat sera were tested for C-reactive protein (CRP) and anti-P. acnes IgG levels.
Main Results:
- Live P. acnes was recoverable from dorsal-lateral prostate lobes for up to 3 months, while ventral lobes cleared earlier.
- Significant focal inflammation was observed in dorsal-lateral lobes up to 3 months post-infection.
- Elevated CRP and IgG levels persisted throughout the experiment, peaking at 3 weeks and 3 months, respectively.
Conclusions:
- P. acnes demonstrates the potential to establish chronic infections within the prostate.
- P. acnes infection can lead to sustained histological inflammation in prostate tissue.
- The developed rat model supports P. acnes as a causative agent for chronic prostate inflammation.
