Abstract:
Introduction: The tight junction (TJ) complexes of the alveolar epithelium regulate lung permeability. Objectives: To determine whether sepsis and mechanical ventilation alter the TJ complexes in the alveolar walls of rat lungs in vivo. Methods: We performed an abdominal sepsis model induced by cecal ligation and puncture (CLP) followed 24 h later by mechanical ventilation (MV) with a protective strategy (Vt= 9 ml/kg+PEEP 5 cmH2O for 4 h) in adult rats (Sprague-Dawley). The groups were (n= 10/group): Sham-without MV (laparotomy only, control group), CLP-without MV, Sham+MV and CLP+MV. We collected lung tissue, bronchoalveolar lavage fluid (BALF) and plasma and we measured the levels of Occludin and ZO1 (ELISA, inmunofluorescence), cytokines (ELISA) and apoptosis (caspase 3 and TUNEL). Results: 1) The levels of cytokines were similar in all groups, except for a decrease of IL1b in the BALF of the CLP+MV group. 2) Compared with the control group, the activity of caspase 3 and apoptosis in rat lungs was increased in the CLP, MV and CLP+MV groups. 3) Compared with the control group, the levels of occludin were increased in the lungs of rats with CLP (with or without MV). Only the combination of CLP a...