The goal of this clinical trial is to learn whether intravesical instillation of human umbilical cord mesenchymal stem cell-derived exosomes combined with sodium hyaluronate is safe and effective for treating radiation cystitis. Radiation cystitis is a complication that may occur after pelvic radiotherapy. Common symptoms include blood in the urine, frequent urination, urgent urination, and painful urination.

The main questions this study aims to answer are:

Can human umbilical cord mesenchymal stem cell-derived exosomes combined with sodium hyaluronate improve blood in the urine in participants with radiation cystitis? Can this combined treatment help repair injury to the bladder lining and blood vessels? What discomfort or medical problems may occur during the treatment?

Researchers will compare four treatment approaches: human umbilical cord mesenchymal stem cell-derived exosomes combined with sodium hyaluronate, human umbilical cord mesenchymal stem cell-derived exosomes alone, sodium hyaluronate alone, and normal saline as a control. By comparing these groups, researchers hope to find out whether the combined treatment works better than either treatment alone or the control treatment.

Participants will:

Be screened to confirm whether they are eligible for the study; Sign an informed consent form and complete baseline assessments; Be randomly assigned to one of four treatment groups; Receive intravesical instillation once a week for 4 weeks; Attend follow-up visits at 1 month, 3 months, and 6 months after treatment; Be assessed for blood in the urine, urinary symptoms, cystoscopy findings, quality of life, and safety.

This study may help provide a new treatment option for radiation cystitis and further evaluate the safety and early effectiveness of this treatment.

Inclusion Criteria:

• Female participants aged 18-80 years.
• History of pelvic radiotherapy, with completion of radiotherapy at least 6 months prior to enrollment.
• Clinically diagnosed with radiation cystitis accompanied by persistent lower urinary tract symptoms, such as urinary frequency, urgency, hematuria, or related symptoms.
• Able and willing to provide written informed consent.

Exclusion Criteria:

• Acute urinary tract infection or active tuberculous cystitis.
• Bladder tumor or bladder metastasis from other malignant tumors.
• Severe cardiac, pulmonary, hepatic, or renal dysfunction (e.g., ALT/AST >3 times the upper limit of normal or serum creatinine above the upper limit of normal).
• Pregnant or breastfeeding women.
• Known allergy to sodium hyaluronate or stem cell-derived products.
• Participation in another clinical trial within the past 3 months.