Comparative Evaluation of Therapeutic Effects of Boric Acid and Triamcinolone in Nasal Polyp Culture

This study aimed to elucidate the therapeutic effects of boric acid (BA) in human nasal polyp cultures, specifically investigating its ability to modulate oxidative stress, inflammation, and remodeling, and to assess its potential as an adjuvant to triamcinolone acetonide (TA). Nasal polyp tissues from 30 patients with CRSwNP, obtained prior to functional endoscopic sinus surgery, were cultured ex vivo for 72 h. Within-patient randomized groups were: control, BA 2.5 mM, TA 10 µM, BA 2.5 mM + TA 10 µM, and BA 2.5 mM + TA 5 µM. At the endpoint, cytokines (IL-2, IL-4, IL-5, IL-13, TNF-α) and MMP-9/TIMP-1 (ELISA/RT-qPCR), oxidative–antioxidant markers (MDA, GSH, CAT, TAS, TOS; spectrophotometry/ELISA), apoptosis and cell cycle (flow cytometry), and histopathology (H&E) were assessed. Relative to the control samples, both BA and TA significantly suppressed type-2 cytokines and TNF-α at protein and mRNA levels (all p < 0.01). Antioxidant responses increased with reductions in MDA and TOS and elevations in TAS and CAT (p < 0.01). MMP-9 decreased while TIMP-1 increased (p < 0.001), indicating improved ECM balance. At the cellular level, early apoptosis increased and G0/G1 accumulation suggested an antiproliferative effect. Histology showed a reduced inflammatory burden and oedema. In human nasal polyp tissue, we observed that BA attenuated inflammation and oxidative stress while supporting tissue homeostasis, demonstrating a multimodal therapeutic signal. Its combined effect profile with corticosteroids supports clinical evaluation of BA as an innovative adjuvant and a potential component of steroid-sparing strategies in CRSwNP management.