Plant Extract Reduced Signs of IPF in Mice
An extract of the plant Lemna minor L., also called duckweed, suppresses the signs and symptoms of idiopathic pulmonary fibrosis (IPF) in disease-induced mice, a study suggests.
More research to evaluate dosing and oral availability is recommended, study authors noted.
Growing evidence suggests that oxidative stress plays a significant role in IPF, a condition characterized by scarring, or fibrosis, of lung tissue, leading to shortness of breath.
Oxidative stress is caused by an imbalance between oxidant and antioxidant production in favor of oxidants, leading to impaired cellular function and tissue damage. Because of exposure to relatively higher oxygen levels, the lungs are susceptible to oxidative stress.
L. minor is a fast-growing freshwater plant with antioxidant and anti-inflammatory potential. It has been used as a herbal remedy to treat scurvy, common colds, and as a diuretic. L. minor also can remove heavy metal contaminants from water.
The aim of this study, conducted by researchers at the Trakia University in Bulgaria, was to investigate the protective effect of L. minor extract on oxidative stress and other signs of fibrosis in mice with induced IPF.
Male BALB/c mice, a common inbred, immunodeficient strain of mice, were exposed to bleomycin to induce IPF. After 33 days, they lost about 24% of their body weight. L. minor extract, administered by injection, significantly reduced bleomycin-induced weight loss.
Lung tissue examination of IPF mice found high numbers of mast cells in the airway walls and blood vessels, which are known to accumulate in conditions characterized by lung fibrosis and are involved in inflammatory processes. Extract treatment suppressed the number of mast cells in lung tissue.
Treatment also reduced the thickness of the tissues that separate the tiny air sacs in the lungs where gas exchanges occur, as well as the deposition of collagen, a protein component of scar tissue, and hydroxyproline, a marker of fibrosis.
There was a significant increase in protein oxidation in IPF mice lung tissue, which was suppressed significantly by L. minor extract. A significant reduction in advanced glycation end products (AGEs), a biomarker associated with aging and the development of many degenerative diseases, also was observed.
The team then evaluated oxidative stress markers, including reactive oxygen species (ROS) and malondialdehyde (MDA). Antioxidant molecules that counterbalance oxidants also were assessed, such as the enzymes superoxide dismutase and catalase, and the antioxidant glutathione (GSH).
Compared to controls, the antioxidants superoxide dismutase, catalase, and GSH were decreased significantly in IPF mice’s lungs, whereas the oxidants ROS and MDA increased significantly.
L. minor extract significantly suppressed induced oxidative damage and promoted the recovery of the antioxidant system, with increases in superoxide dismutase, catalase, and GSH, alongside decreases in ROS and MDA.
Bleomycin-exposed mice showed increases in the levels of pro-inflammatory immune signaling proteins interleukin-1-beta (IL-1-beta), interleukin-6 (IL-6), and TNF-alpha in the lungs. L. minor extract markedly lowered the levels of all three proteins. Similar results were seen in blood samples.
Finally, a statistical analysis found a positive correlation between various oxidative stress parameters, including elevated protein oxidation and AGEs, protein oxidation and MDA, AGEs and MDA, ROS and MDA, IL-1-beta and TNF-alpha, and protein oxidation and IL-6.
L. minor “could be a good antioxidant, anti-inflammatory, and anti-fibrotic alternative [for] IPF prevention,” the authors wrote. “However, the results of the present study highlight the need for further research to determine whether a higher dose of L. minor induced orally … or included as a dietary supplement may be advantageous in terms of the studied parameters.”