Vitamin A reduces lung granulomatous inflammation with eosinophilic and neutrophilic infiltration in Sephadex-treated rats

Vitamin A is known to suppress the activity of the transcription factors, nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), as do glucocorticoids. The possibility that vitamin A exerts various anti-inflammatory effects therefore seems likely. Sephadex beads were administered intravenously to anesthesized rats pretreated with a subcutaneous injection of vitamin A (3000, 10,000, or 30,000 IU/kg) or vehicle once daily for 3 days. After 16 h, the leukocyte differential, tumor necrosis factor (TNF)-α and eotaxin, and the DNA-binding activity of NF-κB were measured in bronchoalveolar lavage fluid (BALF). Additionally, lung histology was assessed using preparations stained with May–Giemsa stain. Sephadex beads caused histological granulomatous changes and eosinophilic and neutrophilic infiltration into the lung, and markedly increased cell counts of eosinophils and neutrophils, concentrations of TNF-α and eotaxin, and NF-κB binding to DNA in BALF. Vitamin A significantly inhibited all responses. Vitamin A may inhibit Sephadex-induced lung granulomatous formation, and eosinophilic and neutrophilic infiltration due to its suppression of TNF-α and eotaxin production, and NF-κB activation.