Effect Of Protective Ventilation On The Tight Junction In Alveolar Epithelium Of Rats With Acute Lung Injury

Experiment A Time course of alveolar epithelial tight junction of rats with acute lung injuryObjective To observe the time course of alveolar epithelial tight junction (TJ) of rats with acute lung injury (ALI).Methods Twenty five SD rats were randomly assigned to five groups: (1) group control, (2) group LPS, (3) group LV2h, mechanical ventilation for 2h on rats with ALI, (4) group LV4h, mechanical ventilation for 4h on rats with ALI and (5) group LV6h, mechanical ventilation for 6h on rats with ALI. ALI was induced by intravenous injection of LPS. Histopathologic evaluation was carried out using semiquantitative scoring (ALI score). Lung edema was indicated by wet/dry ratio. Leakage of FITC-Albumin from blood into bronchoalveolar lavage fluid (A肺泡/A血清) was measured to indicate the alveolar epithelial permeability. Morphologic changes in the TJ proteins were observed by immunofluorescence. Expression of TJ protein, Occludin, was assessed by Western blot and immunofluorescence.Results (1) ALI score in group control was 2.60±0.25, pronouncedly lower than that in group LPS (8.00±0.21), (q=25.74, P < 0.05); Compared with group LV2h (8.02±0.48), ALI scores in group LV4h (7.20±0.40) and group LV6h (7.06±0.23) were significantly decreased (q=3.91 and q=4.58, P < 0.05). (2) Lung W/D in group control was 1.97±0.75, significantly lower than that in group LPS (5.81±0.68) (q=3.33, P < 0.05); while there were no significant differences among group LV2h (4.20±0.53), LV4h (3.68±0.65) and LV6h (3.61±0.28) (P > 0.05). (3) A肺泡/A血清significantly increased in group LPS (1.99±0.23) compared with group control (1.09±0.05) (q=3.33, P < 0.05); compared with group LV2h (3.58±0.47), A肺泡/A血清in group...