Long-term effect of extracorporeal shock wave therapy on attenuating radiation-induced chronic cystitis in rat.

Background: This study tested the long-term effect of extracorporeal shock wave (ECSW) therapy on ameliorating radiotherapy-induced chronic cystitis (CC) in rat. Methods and results: Adult-female SD rats (n = 24) were equally categorized into group 1 (normal control), group 2 (CC induced by radiotherapy with 450 cGy twice with a four-hour interval to the urinary bladder), group 3 [CC with ECSW treatment (0.1 mJ/mm(2)/120 impulses once every 3 days after radiotherapy)]. Bladder specimens were harvested by day 60 after radiotherapy. By day 60, the degree of detrusor contraction was significantly reduced in group 2 than groups 1 and 3, and significantly reduced in group 3 than in group 1 (P < 0.0001). Number of WBC, occulted blood and bacteria were significantly higher in group 2 than in groups 1 and 3 (P < 0.01), but they showed no difference between the latter two groups (P > 0.3). The protein expressions of oxidative stress (NOX-1/NOX-2/oxidized protein), apoptosis (cleaved-caspase-3/cleaved-PARP), DNA-damaged marker (gamma-H2AX), fibrosis (TGF-beta/Smad3) and inflammatory signaling (TLR-4/MYD88/Mal/TRAF6/p-I kappa B alpha/p-NF kappa B/TNF-alpha/MMP-9/COX-2) were significantly higher in group 2 than in group 1, and were significantly reduced in group 3 (all P < 0.001). The cellular expressions of inflammatory (CD14+/CD68+/MIF+/MMP-9), immunoreactive (CD4+/CD8+) and cytokeratin (CK17/CK18) biomarkers, and collagen-deposition/fibrotic areas as well as bladder-damaged score/disruption of the bladder mucosa displayed an identical pattern compared to that of oxidative stress among the three groups (all P < 0.0001). Conclusion: The long-term effect of ECSW treatment was reliable on protecting the urinary bladder from radiation-induced CC.