Effect of dexmedetomidine on gamma-aminobutyric acid receptor expression during ventilator-induced lung injury in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of dexmedetomidine on the expression of gamma-aminobutyric acid(GABAA)receptors during ventilator-induced lung injury(VILI)in rats. Methods Thirty pathogen-free adult male Sprague-Dawley rats,weighing 280-320 g,were divided into 3 groups(n=10 each)using a random number table:control group(group C),group VILI and dexmedetomidine group(group Dex).The rats were mechanically ventilated for 4 h with the tidal volume of 40 ml/kg to establish VILI model. Dexmedetomidine 50 μg/kg was injected intraperitoneally after the rats were anesthetized in group Dex,while the equal volume of normal saline was given instead in C and VILI groups. The animals were sacrificed at 4 h of mechanical ventilation,the lungs were removed for examination of pathological changes which were scored,bronchoalveolar lavage fluid(BALF)was collected for determination of concentrations of total protein,interleukin-1 beta(IL-1β),IL-6 and tumor necrosis factor-alpha(TNF-α),and the lung specimens were obtained for determination of the wet/dry weight ratio(W/D ratio),alveolar fluid clearance(AFC)and expression of GABAA receptors,IL-1β,IL-6 and TNF-α mRNA in lung tissues. Results Compared with group C,the W/D ratio,pathological scores,expression of total protein,IL-1β,IL-6 and TNF-α in BALF and expression of IL-1β,IL-6 and TNF-α mRNA in lung tissues were significantly increased,and the GABAA receptor expression and AFC were decreased in VILI and Dex groups(P<0.05).Compared with group VILI,the W/D ratio,pathological scores,expression of total protein,IL-1β,IL-6 and TNF-α in BALF and expression of IL-1β,IL-6 and TNF-α mRNA in lung tissues were significantly decreased,and the GABAA receptor expression and AFC were increased in group Dex(P<0.05).Conclusion The mechanism by which dexmedetomidine reduces VILI is related to up-regulation of GABAA receptor expression in rats.