Yang et al. Clin Toxicol (Phila). 2011 Apr;49(4):298-302.
Paraquat is a herbicide that is linked to development of Parkinsons. It also is a toxin to lung cells and is used as a model of inducing lung injury in rats. In the current study the investigators wanted to see if administration of bone marrow mesenchymal stem cells had a therapeutic effect on paraquat-induced lung injury in rats.
The investigators used 54 female SD rats that were randomly divided into four groups:
a) Paraquat treated group,
b) Paraquat and bone marrow mesenchymal stem cell treated group,
c) Bone marrow mesenchymal stem cell alone treated group
d) Control untreated group
The stem cells were injected intravenously and animals were sacrificed 14 days after injection.
While animals receiving paraquat alone lived an averaty of 9.6 days, all rats receiving bone marrow mesenchymal stem cells lived more than 14 days. Bone marrow mesenchymal stem cell treatment was associated with less wet lung, decreases in plasma IL-1 and TNF-alpha, decrease in MDA, and decrease in NF-kappa B. Upregulated levels of the antioxidant enzyme superoxide dismutase was observed.
The ability to stimulate repair of the lung by mesenchymal stem cells is not new. Previous studies have shown that mesenchymal stem cells are capable of reducing endotoxin induced lung injury by secretion of keratinocyte growth factor. Other studies have shown that mesenchymal stem cells produce interleukin 1 receptor antagonist in the bleomycine induced model of lung fibrosis.
As with other stem cell therapies described on this website, there is some controversy as to the biological mechanisms by which the stem cells are mediating their therapeutic effect. One possibility is that they are secreting growth factors that stimulate proliferation of endogenous stem cells that are already resident in the lung. The other possibility is that the stem cells are directly differentiating into lung tissue.