Thermosensitive Gel Nasal Spray With Stem Cell Exosomes, Mupirocin, and DNase I for Chronic Sinusitis

This study tests a new nasal spray for adults (18-65 years) with chronic rhinosinusitis (CRS) without nasal polyps. The spray contains a temperature-sensitive gel (thermosensitive gel) that turns into a soft gel inside the nose to slowly release three active ingredients: human umbilical cord mesenchymal stem cell exosomes (hUC-MSC-Exo) to help heal the nasal lining, mupirocin (an antibiotic that kills Staphylococcus aureus bacteria), and DNase I (an enzyme that breaks down thick mucus). The study aims to check the safety of this triple combination and see if it can reduce infection, clear mucus, and improve symptoms. Participants will be randomly assigned to one of three groups: triple spray, a dual spray (without exosomes), or a placebo (gel only). The treatment is used twice daily for 4 weeks, with follow-up visits up to day 90. The study is single-centre, double-blind, and placebo-controlled. Outcome measures include safety (adverse events graded by Common Terminology Criteria for Adverse Events version 5.0, CTCAE v5.0), bacterial clearance rate, changes in nasal endoscopy score (Lund-Kennedy), quality of life (Sino-Nasal Outcome Test-22, SNOT-22), and nasal symptom visual analog scale (VAS).

Inclusion Criteria: * Age 18 to 65 years, both genders * Diagnosis of chronic rhinosinusitis without nasal polyps according to Chinese guidelines (2018), duration \>12 weeks * Nasal endoscopy shows purulent secretions (Lund-Kennedy secretion score ≥1) * Nasal secretion culture positive for Staphylococcus aureus * Sino-Nasal Outcome Test-22 (SNOT-22) score ≥30 * Voluntary signed informed consent Exclusion Criteria: * Sinus surgery within past 6 months, or anatomical abnormalities requiring reoperation * Confirmed allergic fungal rhinosinusitis, odontogenic rhinosinusitis, or nasal polyps * Nasal discharge culture indicating Pseudomonas aeruginosa as primary pathogen * Primary ciliary dyskinesia, cystic fibrosis, or severe immunodeficiency * Use of systemic antibiotics or immunosuppressants within past 4 weeks * Use of intranasal corticosteroids within past 2 weeks * Hypersensitivity to mupirocin, DNase I, or any component of the formulation * Severe renal impairment (estimated Glomerular Filtration Rate, eGFR \