Sambucus nigra Extract Significantly Reduces Inflammation and Restores Bladder Epithelium in Rat Interstitial Cystitis Model

Interstitial cystitis (IC) is a chronic and debilitating bladder condition characterized by pain, urgency, and frequency, with inflammation playing a significant role in its pathophysiology. Current treatments often provide symptomatic relief but do not address the underlying inflammatory processes or tissue damage effectively. This creates a need for novel therapeutic strategies that can modulate inflammation and support tissue regeneration. Sambucus nigra (elderberry) has demonstrated potent antioxidant and anti-inflammatory properties, making its extracts a compelling candidate for investigating therapeutic effects in inflammatory conditions like IC.

Researchers investigated the therapeutic effects of Sambucus nigra extract (SNe) in a preclinical model of interstitial cystitis. Thirty Wistar albino adult female rats were divided into three groups of n=10 each: a control (sham) group, an interstitial cystitis (IC) group, and a treatment group. Rats in the treatment group received oral Sambucus nigra extract at a dose of 0.040 g/kg every other day for 8 weeks. Bladder tissues were subsequently examined using both histological and immunohistochemical methods. Primary endpoints included assessing mast cell counts and the levels of key inflammatory cytokines and growth factors: Interleukin-6 (IL-6), Interleukin-8 (IL-8), Vascular Endothelial Growth Factor (VEGF), and Tumor Necrosis Factor-α (TNF-α).

Bladder sections from the interstitial cystitis group exhibited striking findings of chronic inflammation. In contrast, the Sambucus nigra treatment group showed clear signs of tissue recovery. Histological examination revealed regenerating transitional epithelium, a more compact appearance in the lamina propria, and a notable decrease in both inflammatory cells and mast cells. Specific cytokine analysis further elucidated these anti-inflammatory effects:

Significant improvements were noted in IL-8, TNF-α, and mast cell counts in the treatment group compared to the IC group. While a reduction was also observed in IL-6 and VEGF levels, this particular reduction was not statistically significant. The overall findings indicate that Sambucus nigra effectively mitigates key inflammatory markers and promotes structural recovery in damaged bladder tissue, including the epithelium, smooth muscle, and basal membrane, in this preclinical model.