Soy Protein and Safflower-Seed Oil Attenuate Inflammation and Immune Dysfunction in Rats with Hyperuricemia

A plant-based diet is considered a promising approach for managing hyperuricemia (HUA). This study examined the effects of soy protein and plant-based oils on HUA-induced inflammation and immune dysfunction. Male Wistar rats, induced with HUA using oxonic acid and uric acid (UA), were fed casein or soy protein with palm or safflower oil (2 × 2 factorial design) for 8 weeks. HUA rats had lower serum albumin and T cell percentages in peripheral blood leukocytes (PBLs) and splenocytes, along with increased leukocyte counts and spleen weights, compared to healthy rats (p < 0.05). Soy protein improved HUA-induced reductions in albumin, while safflower-seed oil ameliorated reductions in albumin, plasma interleukin (IL)-4, and T-suppressor splenocytes, and mitigated elevated serum UA, plasma IL-6, and B leukocytes (two-way ANOVA, p < 0.05). In PBL, soy protein alleviated HUA-induced decreases in TNF-α, casein and palm oil increased IL-6, and casein further reduced IFN-γ production. Under Con A stimulation, casein and safflower-seed oil alleviated decreases in IL-6 and IL-10, respectively, while under LPS stimulation, casein further increased TNF-α production. In splenocytes, soy protein and safflower-seed oil reduced HUA-induced increases in TNF-α and increased IL-10, and safflower-seed oil increased IL-6 production. Under Con A stimulation, soy protein and safflower-seed oil reduced TNF-α and increased IL-10 production in splenocytes. The findings suggest that soy protein and safflower-seed oil may counteract HUA-related inflammation, alleviate monocyte activation, and enhance Th2 immune response in HUA. A plant-based diet rich in soy protein and safflower-seed oil may help manage HUA and associated inflammation and immune dysfunction.