Compound in Traditional Chinese Medicine Seen to Block Lung Fibrosis in Mice
Salvianolic acid B, a compound isolated from red sage and a main component of the traditional Chinese medicine known as Yiqihuoxue formula, prevented fibrotic changes both in bleomycin-treated mice and in cell culture models. These findings indicate the compound may be worth exploring as a less toxic alternative to treating fibrosis.
Traditional Chinese medicine is often used to alleviate symptoms of fibrotic disorders, and patients often turn to such remedies when conventional drugs fail, or their use is hampered by side effects.
A research group from Fudan University in China recently found that the traditional blend Yiqihuoxue formula could lessen skin and lung fibrosis. Following on this lead, the team investigated the formula’s components to identify a compound that might be responsible.
Two major ingredients in this traditional Chinese medicine are the flowering plant Huáng Qí and red sage. Researchers tested other minor components for anti-fibrotic activity, but then focused on a compound called Salvianolic acid B, the main constituent of red sage.
To determine whether this substance could affect fibrosis in a living animal, they treated mice with bleomycin — a compound commonly used to trigger fibrosis in experimental animals. Part of these mice were also given Salvianolic acid B.
Mice treated with Salvianolic acid B developed less fibrotic damage of the lung alveoli than mice receiving no treatment. The animals also had only about half the amount of collagen in their lung tissue compared to non-treated animals — a feature that coincided with a lower expression of collagen genes. Importantly, the mice did not seem to experience any toxic effects from the treatment.
Researchers next went on to study fibroblasts in a lab dish, and noted that Salvianolic acid B was able to block the specialization of these cells into myofibroblasts when exposed to the pro-fibrotic factor TGF-β. The study, “Salvianolic Acid B Attenuates Experimental Pulmonary Fibrosis through Inhibition of the TGF-β Signaling Pathway,“ indicated that this was likely mediated by preventing changes in gene expression and cell signaling pathways, induced by TGF-β.
Findings, published in the journal Scientific Reports, showed that Salvianolic acid B also had similar properties when tested in a cell type derived from human lung epithelium, where scientists triggered fibrosis using both TGF-β and TNF-α, an inflammatory molecule also believed to be involved in fibrotic processes.
Since newly approved anti-fibrotic drugs are far from optimal and restricted to patients without liver and kidney damage, the study suggests further exploring Salvianolic acid B as a potential new drug for pulmonary fibrosis.