The Alveolar Septal Thickness and Type II Pneumocytes Number in Irradiated Lungs, Time Expression and the Effect of Pentoxifylline

Abstract

Purpose: We studied the relationship between type II pneumocytes number and alveolar septal thickness during different time after sublethal whole-thorax irradiation of rats and we investigated the influence of pentoxifylline (TNF-α inhibitor). Materials and methods: Wistar rats were exposed to 15 Gy thoracic irradiation and pentoxifylline (35 mg/kg) twice a week. Lungs were examined histologically and imunohistochemically at intervals ranging from 1-12 weeks and alveolar septal thickness, number of type II pneumocytes (identified by immunoreactivity for cytokeratin 18), and neutrophile granulocytes were counted. Results: Significant increase of alveolar septal thickness and type II pneumocytes depletion 3 weeks after irradiation were found. Correlation of these markers was r = -0.759. Pentoxifylline significantly inhibits increased alveolar septal thickness without the influence on type II pneumocytes number. Neutrophil penetration started 5 weeks after irradiation in non-treated animals, 8 weeks after irradiation in PTX-treated rats. Conclusions: We suggest that pneumocytes depletion is linked to increased vascular permeability, and pentoxifylline therapy does not influence on pneumocytes kinetics after irradiation.

Keywords

• γ-Irradiation
• Lung
• Pentoxifylline
• Pneumocytes type II
• Interstitial edema