Objective      To investigate the effect of dimethyl sulfoxide (DMSO) on the treatment of protamine sulfate (PS)-induced interstitial cystitis in rats.       Methods      Totally

48 SD rats were randomized into a normal group

a PS perfusion group

a PS+DMSO group

and a saline perfusion group (NS group)

12 rats in each group. The normal group was not given any treatment. The PS group was treated with 0.5 mL

30 mg/mL PS by bladder perfusion for 30 min. The PS+DMSO group was treated with 0.5 mL

30 mg/mL PS+DMSO (PS dissolved in 50% DMSO) by bladder perfusion for 30 min. The NS group was treated with 0.5 mL normal saline by bladder perfusion for 30 min. The rats were treated once in a week and the treatment lasted for 4 weeks. After 4 weeks

HE staining and toluidine blue staining were used for pathological scoring and mast cell counting. Urodynamics and muscle strip test were used for the evaluation of bladder function and muscle contraction. The changes of superoxide peroxidase 2 (SOD2)

glutathione peroxidase (GSH-Px)

interleukin 6 (IL-6)

interleukin-1β (IL-1β)

and tumor necrosis factor-α (TNF-α) were measured by Western blotting.       Results      Compared with the PS group

the rat bladder pathological scores (3.00±0.00 vs 0.83±0.40

P0.05)

mast cell count (19.66±2.16 vs 6.16±1.16

P0.05)

and expression of inflammatory cytokines (IL-6

IL-1β and TNF-α

P0.05) were significantly decreased in the PS+DMSO group

and the antioxidant enzymes (SOD2 and GSH-Px) were significantly increased (P0.05). For bladder function

compared with the PS group

the PS+DMSO group showed lower micturition frequency (24.83±3.06 vs 9.83±1.47

P0.05)

shorter intercontraction interval (2.42±0.37 vs 6.40± 0.57

P0.05)

and lower muscle contraction frequency (6.93±0.97 vs 4.94±0.73

P0.05).       Conclusion      DMSO alleviates the PS-induced rat cystitis by reducing inflammation and oxidative stress.