Nigella sativa Oil Supplementation Ameliorates Symptoms and Reduces Disease Progression Biomarkers in Rats with Adjuvant-Induced Arthritis

Nigella sativa cold-pressed oil (NSO) is rich in nutrients and biologically active compounds. This study aimed to evaluate its effects on symptoms and serum levels of inflammatory and disease activity markers in rats with Freund’s adjuvant-induced arthritis (AIA). Animals were treated orally with NSO at doses of 1 and 3 mL/kg for two weeks before arthritis induction and throughout the experiment. Hind paw edema and nociceptive thresholds were measured by plethysmometer, Hargreaves apparatus, and Randall–Selitto test, respectively. At the end of the experiment, TNF-α, IL-1β, IL-10, brain-derived neurotrophic factor (BDNF), and neuropeptide Y (NPY) serum levels were measured. NSO preventive administration significantly reduced paw edema of the affected hind paw, along with an increase in the nociceptive threshold to both thermal and mechanical stimuli. Administration of NSO resulted in a significant reduction in serum levels of IL-1β and NPY (p < 0.01 and p < 0.05, respectively), while TNF-α and IL-10 levels remained comparable to those in the untreated AIA control group. These findings indicate that NSO exerts anti-inflammatory and analgesic effects and modulates circulating IL-1β and NPY (an independent marker associated with disease activity) in experimental arthritis.