Immunostimulatory, anti-inflammatory, and immunomodulatory effects of Gum Arabic: regulation of cytokines and phagocytic function in rats

Introduction: The role of natural dietary fibers in supporting immune function and systemic physiological responses is increasingly recognized. This study evaluated the effect of long-term oral administration of gum arabic (GA) on the immune function of rats. Method: Seventy-six adult male Wistar rats were assigned to five groups: controls, GA treated (5% or 10% in drinking water for 6 weeks), and GA combined with LPS or dexamethasone, alongside corresponding LPS and dexamethasone controls.Phagocytic, histological, and immune markers were estimated and evaluated statistically by using one-way ANOVA followed by Duncan's multiple range test. Results: GA treatment significantly increased serum complement-3 levels, lysozyme activity, immunoglobulin M (IgM), and nitric oxide (p < 0.05). GA also increased phagocytic index, neopterin, and intestinal mucosal eosinophil count, while spleen weight and mucosal mast cell count remained unchanged. GA mitigated the inhibitory effects of intramuscular dexamethasone on immune parameters and improved intravascular carbon clearance, and effectively attenuated the LPS induced increase in the pro-inflammatory cytokines (IL-1α, IL-4, IL-6, and TNF-α). Conclusion: These findings suggest that GA modulates selected immune parameters, enhances innate immune responses, and maintains systemic immune responsiveness under both normal and challenged conditions in rats.