Synergistic protective effects of pine pollen extract and fucoidan on adriamycin-induced acute kidney injury via regulation of oxidative stress and inflammatory pathways.

Adriamycin (ADR)-induced nephrotoxicity remains a significant clinical challenge that limits its chemotherapeutic utility, necessitating the development of effective multi-target renoprotective strategies. Although natural polysaccharides show great promise, the synergistic potential of combining pine pollen aqueous extract (PPAE) and fucoidan (FUC) has been unexplored. This study aimed to investigate the synergistic protective effects of PPAE and FUC against ADR-induced kidney injury and to elucidate the underlying molecular mechanisms. In ADR-treated Human Kidney-2 (HK-2) cells, PPAE+FUC exhibited strong synergy (CI = 0.3-0.7), resulting in improved cell viability, reduced apoptosis, decreased LDH and ATP leakage, and attenuated oxidative stress. RNA-seq profiling confirmed a clear convergence on pathways governing oxidative stress, apoptosis, and inflammation. In vivo results corroborated these findings, as the combination treatment significantly attenuated ADR-induced renal dysfunction, histological damage, and systemic inflammation while restoring redox homeostasis. Mechanistically, the combination was highly associated with the modulation of Nrf2-Keap1-GPX4 and NF-κB signaling axes, which simultaneously bolstered antioxidant defenses and suppressed inflammatory cascades via inhibiting p65 and IκBα phosphorylation. Furthermore, 16S rDNA sequencing revealed that PPAE+FUC potentially reshaped the gut microbiota by reconstituting the probiotic genus Akkermansia and normalizing the Firmicutes/Bacteroidota ratio. Ultimately, our study confirms that the PPAE and FUC combination exerts a multi-target synergistic effect through the attenuation of oxidative stress and inflammation, with concomitant alterations in gut microbiota composition. These findings provide a robust evidence-based rationale for this natural polysaccharide combination as a safe and innovative nutritional strategy to mitigate chemotherapy-associated renal injury.