Nano-enabled delivery of EGCG ameliorates silica-induced pulmonary fibrosis in rats

Silicosis is the most serious occupational pulmonary fibrosis caused by excessive inhalation of silica particles, whereas viable therapeutic choices are constrained. Epigallocatechin gallate (EGCG) presents massive health benefits, but unfortunately with stability absence. Here, encapsulation of EGCG in poly(n-butylcyanoacrylate) nanoparticles (EGCG/PBCA-NPs) were fabricated by self-polymerization for gastrointestinal delivery in silicosis fibrosis treatment. The obtained nano-enabled delivery of EGCG was produced using a medical adhesive approved by FDA as carrier, and presented spherical particles with approximate diameter of 160 nm, a narrow PDI value of 0.2, Zeta potential value of 30 mV as well as a high EGCG incorporation (90 %) and loading efficiency (20 %). In evaluating the protect effects of nano-formulations, EGCG/PBCA-NPs shown excellent stability in gastric fluid with pH-triggered release in intestine and strong EGCG gastrointestinal retention against degradation. After daily gastrointestinal administration, EGCG/PBCA-NPs exhibited the superior anti-fibrosis efficacy in silicosis model rats induced by silica, involving lung index decline, hydroxyproline content decrease, histological improvement, collagen accumulation reduction and α-SMA down-regulation in comparison with naked EGCG. These results strongly demonstrated that PBCA-based NPs may be a promising nano-enabled delivery carrier for enhancing the gastrointestinal stability and anti-fibrotic effects of EGCG.