HMGB1 and chronic cystitis: Furthermore, our findings that disulfide HMGB1 mediates bladder pain in a model with no overt bladder inflammation extend the findings of Tanaka et al [5] who found that systemic HMGB1 antagonists could prevent bladder pain after chemical (cyclophosphamide) injury of the bladder but did not affect inflammatory changes in this chemical cystitis model.