Protective effect of Broussonetia papyrifera leaf polysaccharides on intestinal integrity in a rat model of diet-induced oxidative stress

This study aimed to investigate the effect of Broussonetia papyrifera polysaccharides (BPP) on the jejunal intestinal integrity of rats ingesting oxidized fish oil (OFO) induced oxidative stress. Polysaccharides (Mw 16,956 Da) containing carboxyl groups were extracted from Broussonetia papyrifera leaves. In vitro antioxidant assays showed that this polysaccharide possessed antioxidant capabilities. Thirty-two male weaned rats were allocated into two groups orally infused BPP solution and PBS for 26 days, respectively. From day 9 to day 26, half of the rats in each group were fed food containing OFO, where the lipid peroxidation can induce intestinal oxidative stress. OFO administration resulted in diarrhea, decreased growth performance (p < 0.01), impaired jejunal morphology (p < 0.05) and antioxidant capacity (p < 0.01), increased the levels of ROS and its related products, IL-1β and IL-17 (p < 0.01) of jejunum, as well as down-regulated Bcl-2/Bax (p < 0.01) and Nrf2 signaling (p < 0.01) of jejunum in rats. BPP gavage effectively alleviated the negative effects of OFO on growth performance, morphology, enterocyte apoptosis, antioxidant capacity and inflammation of jejunum (p < 0.05) in rats. In the oxidative stress model cell assay, the use of receptor inhibitors inhibited the enhancement of antioxidant capacity by BPP. These results suggested that BPP protected intestinal morphology, thus improving growth performance and reducing diarrhea in rats ingesting OFO. This protective effect may be attributed to scavenging free radicals and activating the Nrf2 pathway, which enhances antioxidant capacity, consequently reducing inflammation and mitigating intestinal cell death.