The protective effect of hydrogen sulfide on systemic sclerosis associated skin and lung fibrosis in mice model

Systemic sclerosis (SSc) caused fibrosis can be fatal and it still lack of effective treatment. Hydrogen sulfide (H2S) appears to be an attractive therapeutic candidates. This study aimed to investigate the protective effect of H2S on SSc-associated skin and lung fibrosis.

We developed a model of SSc by subcutaneous injecting BLM to female C3H mice. The mice received daily subcutaneous injections of NaHS (56 and 112 μg/kg), an H2S donor. On days 7, 28, and 42, the mice were killed and blood samples were collected to measure the plasma H2S concentration, the skin and lung tissues was harvested for microscopic examination, immunohistochemistry and quantify biological parameters (hydroxyproline content, RT-qPCR and Western blot).

In model group, the dermis of skin tissues at different time points gradually thickened, collagen deposition increased. The lung tissues presented pathological changes such as obvious inflammatory cell infiltration, increased collagen deposition and the plasma H2S concentrations points significantly decreased. Administration of NaHS markedly decreased the biomarkers of fibrosis such as α-smooth muscle actin, collagen-I, collagen-III, fibronectin, transforming growth factor-β1, Smad2/3 phosphorylation and inflammation including the marker protein of monocyte/macrophage and monocyte chemoattractant protein-1 in the lung. Compared to the low dose group, the expression in the high dose group have decreased trend, but the difference was not significant.

We demonstrate the beneficial effects of H2S on SSc-associated skin and lung fibrosis. H2S may be a potential therapy against this intractable disease.