Lycium ruthenicum Murr. Polysaccharide Attenuates Bleomycin-Induced Pulmonary Fibrosis in Mice by Modulating Inflammation, Antioxidant Defense, and Gut Microbiota

Lycium ruthenicum Murr. polysaccharides (LRP), the major constituents of black goji berry, exhibit diverse biological activities. Pulmonary fibrosis (PF) frequently arises as a long-term consequence of acute lung injury and is marked by progressive scarring of lung tissue and an irreversible decline in pulmonary function. Persistent inflammatory responses, oxidative stress, and disturbance of the gut–lung axis are closely related to the development of PF. This study aimed to extract LRP from black goji berry and systematically evaluate its protective effects and underlying mechanisms in a bleomycin-induced murine model of PF. The results show that LRP treatment markedly attenuated alveolar structural disruption, inflammatory cell infiltration, and fibrotic lesions. These protective effects were associated with the modulation of inflammatory cytokines and the enhancement of antioxidant capacity through increased superoxide dismutase activity and glutathione levels. Furthermore, LRP reshaped the gut microbiotal community structure. Collectively, these findings provide new insights into the pulmonary protective properties of LRP and support its potential as a promising natural therapeutic agent for PF.