Non-Invasive Radiofrequency Hyperthermia Attenuates HMGB1/TLR4/NF-κB Inflammatory Axis in a Chronic Prostatitis/Chronic Pelvic Pain Syndrome Rat Model.

Purpose: The primary goal of this study is to evaluate the effect of the non-invasive radiofrequency hyperthermia (RFHT) device on chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) rat model and investigate the underlying mechanism.

Materials and methods: In this study, Sprague-Dawley rats were randomly distributed into three groups: (1) normal control group, (2) CP/CPPS group, and (3) RFHT group. CP/CPPS rat models were induced by 17β-estradiol and dihydrotestosterone for 4 weeks and RFHT was administered for 5 weeks after model establishment. During RFHT administration, core body temperatures were continuously monitored with a rectal probe. After administering RFHT, we assessed pain index for all groups and collected prostate tissues for Western blot analysis, immunofluorescence, and immunohistochemistry. We also collected adjacent organs to the prostate including urinary bladder, testes, and rectum for safety assessment via H&E staining along with a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling assay.

Results: After administering RFHT, pain in rats was significantly alleviated compared to the CP/CPPS group. RFHT reduced high-mobility group box 1 (HMGB1) expression and improved inflammation by downregulating subsequent proinflammatory cytokines through inhibition of the toll-like receptor 4 (TLR4)-nuclear factor kappa B (NF-κB) pathway. In prostate-adjacent organs, no significant histological alteration or inflammatory infiltration was detected. The area of cell death also did not increase significantly after RFHT.

Conclusions: In conclusion, RFHT demonstrated anti-inflammatory effects by inhibiting the HMGB1-TLR4-NF-κB pathway in CP/CPPS rat models. This suggests that RFHT could serve as a safe and promising therapeutic strategy for CP/CPPS.