Effect of glucocorticoid on MIP-1α and NF-κB expressing in lung of rat subjecting to mechanical ventilation with high tidal volume

Abstract

Objective To observe the content of macrophage inflammatory protein-1α(MIP-1α)in plasma and bronchoalveolar lavage fluid (BALF) and the expressions of MIP-1α mRNA and nuclear factor-kappa B( NFκB)p65 mRNA in the lung of rats subjected to mechanical ventilation with high tidal volume. Method Thirty-two healthy Wistar rats were randomly ( random number) divided into control group, ventilator induced lung injury (VILI) group,dexamethasone (DEX) group and budesonide (BUD) group. The content of MIP-1α in plasma and BALF were measured with ELJSA and the expressions of MIP-1α mRNA and NF-κBp65 mRNA in lung of rat were detected by RT-PCR. The data distributed were expressed as (-x) ± s and were compared among 4 groups. Furthermore, the correlation between the content of MIP-1α and the expression of MIP-1α mRNA, and the correlation between the expression of MIP-1α mRNA and the expression of NF-κBp65 mRNA were analyzed in the latter three groups. Results With lessened lung injury ,the content of MIP-1αin plasma and BALF and the expressions of MIP-1α mRNA and NF-κBp65 mRNA in lungs of rats of DEX and BUD groups were significantly lower than those in VILI group ( P ＜ 0.001 ). Although the content of MIP-1α in plasma and BALF and the expressions of MIP-1α mRNA and NF-κBp65 mRNA in lungs of rats of BUD group were higher than those of DEX group, but no significant differences were found between them ( P ＞ 0.05). Correlation study showed that positive correlations were xisted between the MIP-1α in plasma and the expression of MIP-1α mRNA in the lungs ( r = 0.895, P ＜ 0.05)and between the expression of MIP-1α mRNA and the expression of NF-κBp65 mRNA in the lungs ( r=0.801, P ＜ 0.05). Conclusions Glucocorticoid could down-regulate the expression of MIP-1α mRNA by inhibiting the activity of NF-κB in the lungs and may have preventive and therapeutic effect to VILI to some extent. The effect of glucocorticoid used locally against VILI is simnilar to that of systemic administration with lesser adverse reactions. Key words: Mechanical ventilation; Lung injury; Macrophage inflammatory protein-1α; Nuclear factorkappa B; Glucocorticoid; Bronchoalveolar lavage fluid; Budesonide; Inflammation