Silibinin mitigates AKI-to-CKD transition via MAPK and PI3K/AKT signaling pathways in Ischemia-Reperfusion injury.

The transition from acute kidney injury (AKI) to chronic kidney disease (CKD) remains a critical clinical challenge with limited therapeutic options. To our knowledge, this was the first study to investigate the renoprotective effects of silibinin, a flavonolignan from Silybum marianum, in mitigating AKI-to-CKD progression via modulation of MAPK and PI3K/AKT signaling pathways-addressing a critical unmet need, as no targeted therapies currently exist to block this transition. For in vivo evaluation, a mice renal ischemia-reperfusion injury (IRI) model was established, where 45 min of ischemia was followed by reperfusion for 1 day (AKI) or 14 days (CKD) across experimental groups. Human renal proximal tubular (HK-2) cells were utilized for in vitro modeling, including hypoxia/reoxygenation (H/R) model and TGF-β1-induced fibrosis. Bioinformatics analysis was employed for target prediction of silibinin. Results showed that silibinin significantly decreased serum creatinine, blood urea nitrogen, oxidative stress, inflammation, and apoptosis induced by IRI. The HE, Masson and Sirius Red staining showed that silibinin decreased the kidney damage and collagen deposition dramatically. Mechanistically, silibinin enhanced PI3K/AKT phosphorylation, suppressed phosphorylation of MAPK components (p38, ERK1/2, JNK), elevated antioxidant enzyme activity, reduced ROS/malondialdehyde levels, inhibited pro-inflammatory cytokine release, downregulated Bax/cleaved caspase-3 expression, and upregulated the anti-apoptotic factor Bcl-2. These effects were recapitulated in vitro, where silibinin mitigated H/R and TGF-β1-driven cellular injury by restoring redox balance and modulating dual signaling axes. Collectively, our findings demonstrated silibinin as a multi-target therapeutic candidate that impedes AKI-CKD transition via coordinated regulation of PI3K/AKT and MAPK pathways. These findings position silibinin as a promising agent for clinical intervention, potentially improving long-term renal outcomes in AKI patients at risk of progressing to CKD.