Low Molecular Weight Fucoidan Inhibits Pulmonary Fibrosis In Vivo and In Vitro via Antioxidant Activity

Area of Science:

• Marine Biotechnology
• Pharmacology
• Biochemistry

Background:

• Pulmonary fibrosis is a debilitating lung disease characterized by excessive collagen deposition and oxidative stress.
• Fucoidan, a sulfated polysaccharide from brown algae like Laminaria japonica, exhibits various bioactivities.
• Low molecular weight fucoidan (LMWF) may possess enhanced therapeutic properties compared to native fucoidan.

Purpose of the Study:

• To investigate the anti-fibrotic effects of LMWF derived from Laminaria japonica.
• To evaluate the role of antioxidant activity in LMWF's therapeutic mechanism against pulmonary fibrosis.
• To assess LMWF's efficacy both *in vivo* using a bleomycin-induced mouse model and *in vitro* using TGF-treated A549 cells.

Main Methods:

• Extraction and degradation of sulfated polysaccharides from Laminaria japonica to obtain LMWF.
• *In vivo* studies involved bleomycin-induced pulmonary fibrosis in mice, assessed via H&E, Masson's trichrome, and Sirius red staining.
• *In vitro* studies utilized TGF-treated A549 cells to evaluate LMWF's effects on cell morphology and antioxidant factors.

Main Results:

• Bleomycin induced significant pathological changes and collagen deposition in mouse lung tissue.
• LMWF treatment effectively inhibited collagen deposition and the expression of fibrosis markers in vivo.
• LMWF demonstrated antioxidant activity by regulating antioxidant factors and reducing oxidative stress in lung tissue and improving TGF-induced cell morphology.

Conclusions:

• Low molecular weight fucoidan (LMWF) from Laminaria japonica possesses significant anti-fibrotic properties.
• The therapeutic effects of LMWF are mediated through its potent antioxidant activity.
• LMWF represents a promising natural compound for the development of novel treatments for pulmonary fibrosis.