Effects of silver nanoparticles-polysaccharide on bleomycin-induced pulmonary fibrosis in rats.

OBJECTIVES: The first goal of this study was to synthesize the silver nanoparticles Alcaligenes xylosoxidans exopolysaccharide (Ag-AXEPS). The second objective was to analyse the role of Ag-AXEPS nanoparticles (NPS) in treating bleomycin (BLM)-induced lung fibrosis. METHODS: Intratracheal bleomycin (2.5 U/kg) was administered to prompt pulmonary fibrosis in rats, and pulmonary fibrosis was treated with Ag-AXEPS nanoparticles (100 ppm/twice a week for four weeks). KEY FINDINGS: Ag-AXEPS nanoparticles significantly decreased the diversity of pulmonary inflammatory agents in rats with BLM-induced fibrosis. Reduced levels of respiratory tumor necrosis factor-alpha, monocyte chemotactic protein-1, matrix metalloproteinases (MMP-2 and MMP-9) were observed on treatment with synthesized Ag-AXEPS. Similarly, the treatment decreased IL-12, mRNA levels of BAX and plasma fibrosis markers like N-terminal procollagen III propeptide and transforming growth factor-ß1. On the other hand, the treatment increased mRNA BCL2 and total antioxidant capacity. It also lowered the level of fibrosis, as was shown by a quantified pathologic study of hematoxylin-eosin-stained lung parts. The treatment, however, ensured that lung collagen was restored, as assessed by Masson's trichrome stain, and that overall survival was increased and enhanced. CONCLUSIONS: Our work showed that nanoparticles could be obtained at 37°C and may be a possible pulmonary fibrosis therapeutic agent.

Histamine, cyclic AMP, and gastric secretion in the dog.

Canine gastric mucosal cyclic AMP content was determined at 1, 5, 30, 60, and 120 min after commencing a 2-hr continuous intravenous infusion of histamine of sufficient dose to elicit a brisk acid secretory response from the dog stomach. The increase in acid output was significant at 30 min and stabilized at the stimulated level for the duration of histamine infusion. By contrast, there was no significant increase in mucosal cyclic AMP content at any time of measurement. Our findings indicate that the acid secretory response of the canine stomach to histamine does not require prior accumulation of cyclic AMP in the mucosal tissue.