Phentolamine Protects against Apoptosis and Inflammation in a Neonatal Pneumonia Cell Model Induced by LPS by Regulating the TrkA/Akt Signaling Pathways

Abstract

Background: Phentolamine is an α-adrenergic receptor blocker that can be used to treat neonatal pneumonia, but its underlying mechanism is unclear. The purpose of this study is to probe the function of phentolamine on lipopolysaccharide (LPS)-induced inflammation and cell death in an in vitro model of neonatal pneumonia. Methods: Human MRC-5 cells were incubated with varying doses of phentolamine in vitro to evaluate cell viability. Subsequently, LPS was introduced to further investigate the combined effects of phentolamine and LPS on cell viability and apoptosis in MRC-5 cells. The effect of phentolamine/LPS treatment on the Neurotrophic Tyrosine Kinase Receptor A (TrkA)/Protein Kinase B (Akt) signaling pathway and the phosphorylation of pathway proteins in MRC-5 cells was further analyzed via western blot. Additionally, knockout of TrkA and Akt genes in MRC-5 cells was performed to explore the effects of phentolamine/LPS treatment on cell viability, apoptosis levels, and inflammatory factor levels in MRC-5 cells. Results: Preincubation of MRC-5 cells with a low concentration of phentolamine (≤6 µg/mL) protected against LPS-induced cell inflammatory injury. Phentolamine promoted both TrkA and Akt phosphorylation and Akt activation induced by LPS in MRC-5 cells. The protective effect of phentolamine against LPS-induced apoptosis and inflammation was significantly reduced in response to TrkA or Akt gene knockdown in MRC-5 cells. Conclusions: Phentolamine may protect LPS-induced apoptosis and inflammation by activating the TrkA and Akt signaling pathways.