Protective effect of dietary fiber from sweet potato (Ipomoea batatasL.) against lead-induced renal injury by inhibiting oxidative stress via AMPK/SIRT1/PGC1α signaling pathways

Dietary fiber (DF) is the main component of sweet potato residue, which has a variety of health benefits. However, the preventive effect of DF from sweet potato on lead (Pb)-induced renal injury remains unclear. This study identified the proximate composition and chemical components of DF extracted by ultrasound-assisted enzymatic hydrolysis. The administration of ordinary dietary fiber (ODF) and high-soluble dietary fiber (HSDF) decreased the blood and kidney Pb concentrations of Pb-exposed mice. Moreover, profound Pb-induced elevations of reactive oxygen species, malondialdehyde level, and depletion of intracellular glutathione level in kidney were suppressed by treatment with HSDF. Compared to the ODF group, HSDF activated AMP-activated protein kinase (AMPK)/silent information regulator T1 (SIRT1)/peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α) signaling in kidney, which directly regulates superoxide dismutase (SOD) and nuclear respiratory factors (NRF1)/mitochondrial transcription factor A (TFAM). In conclusion, HSDF supplementation ameliorates Pb-induced renal injury by inhibiting oxidative stress. Practical applications In China, sweet potato residue is discarded as waste, which causes environmental pollution. Sweet potato residue can be a cheap and widely available resource of DF, which was extracted by ultrasound-assisted enzymatic hydrolysis. This study provides biological evidence that supports the use of DF from sweet potato to prevent Pb accumulation and protect the kidney, thereby indicating that DF has a great potential to be used as natural Pb-excreting agent and functional ingredient in food products.