Expression Of Cav-1 And NF-кB In Mechanical Ventilator-associated Lung Injury Of Rat

Objective:To explore the effect of caveolin-1 to lung tissues via influence the NF-кB signal transduction pathway by observing the expression changes of caveolin-1,NF-кB p65 and IL-8 in high tidal volume mechanical ventilation.Methods:Twenty-four healthy male SD rats were randomly divided into three groups: control group,high tidal volume half an hour group(group H-VT0.5h),high tidal volume two hour group(group H-VT2h).The pathologyical changes of the lung was observed under light microscope; the expression of caveolin-1 in lung tissues of rat were detected by immunohistochemistry; the expression levels of NF-кB p65 m RNA in lung tissues were measured by reverse transcription-polymerase chain reaction(RT-PCR); The lung wet/dry weight ratio(W/D) was calculated. The levels of IL-8 in bronchoalveolar lavage fluid(BALF) were measured by enzyme-linked immunosorbent assay(ELISA). Then analyze the correlativity of cav-1 and NF-кB p65.Results:1. The expression of cav-1 in lung tissues of rats: H-VT2 h group was higher than control group and H-VT0.5h group,the differences were statistically significant(all P<0.05);H-VT0.5h group was higher than control group,the differences were not statistically significant(all P>0.05).2. The expression of NF-кB p65 m RNA in lung tissues of rats: H-VT2 h group washigher than control group and H-VT0.5h group(all P < 0.05); H-VT0.5h group was no statistical differences existed compared with control group(all P>0.05).3. The expression of IL-8 in BALF: H-VT2 hgroup was higher than control group and H-VT0.5h group(all P < 0.05);Compared with control group there were no statistical differences existed of expression of IL-8 in BALF of H-VT0.5h group(all P>0.05).4. The lung wet/dry weight ratio of lung tissues of rats: H-VT2 h group was higher than control group and H-VT0.5h group,the differences were statistically significant(all P <0.05); H-VT0.5h group was higher than control group,the differences were not statistically significant(all P>0.05).5. the correlation analysis between cav-1 and NF-кB p65: the correlation analysis between cav-1 and NF-кB p65 in lung tissues of rats was positively correlated(r=0.820, P<0.01).6. Histopatholosical findings under light microscope: the structure of alveolar in control group rats was normal; the alveolar structure of H-VT0.5h group was relatively intact,alveolar septa was slightly thickening and edema; the structure of alveolar of H-VT2 h group was significantly damaged, alveolar septa obviously thickening and edema,a lot of inflammatory cells infiltrate,and there were a large amount of exudations in alveolar cavities.Conclusions:The high tidal volume mechanical ventilation could increase the expression of cav-1,and further activate the NF-кB signaling pathway, then promote the release of inflammatory cytokines, thus lead to the VILI.