Role of aryl hydrocarbon receptor in down-regulation of Clara cell secretory protein expression during endotoxin-induced lung injury in rats / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of aryl hydrocarbon receptor (AhR) in the down-regulation of Clara cell secretory protein (CCSP) expression during endotoxin-induced lung injury in rats.Methods:Twenty-four clean-grade healthy male Sprague-Dawley rats, aged 8 weeks, weighing 200-250 g, were divided into 4 groups ( n=6 each) using a random number table method: normal control group (group C), acute lung injury (ALI) group, ALI+ AhR antagonist group, and ALI+ vehicle group. Lipopolysaccharide(LPS) 1 mg/kg was intratracheally instilled to develop the model of lung injury, while the equal volume of normal saline was given instead in group C. At 2 h before LPS injection, AhR antagonist 6, 2′, 4′-trimethoxyflavone solution 5 mg/kg (diluted to 1 ml in dimethyl sulfoxide solution) was intraperitoneally injected in ALI+ AhR antagonist group, while dimethyl sulfoxide solution 1 ml was given in ALI+ vehicle group. The rats were sacrificed under anesthesia at 48 h after LPS administration. The left lung was lavaged and the broncho-alveolar lavage fluid (BALF) was collected for determination of the concentrations of CCSP by enzyme-linked immunosorbent assay, and the expression of CCSP in the bronchial epithelium in right lung tissues was determined by immunohistochemistry. Results:Compared with group C, the expression of CCSP in the bronchial epithelium was significantly down-regulated, and the concentrations of CCSP in BALF were decreased in the other three groups ( P<0.05 or 0.01). Compared with ALI group and ALI+ vehicle group, the histopathological injury was significantly reduced, the expression of CCSP in the bronchial epithelium was up-regulated, and the concentrations of CCSP in BALF were increased in ALI+ AhR antagonist group ( P<0.01). Conclusions:AhR partially mediates the down-regulation of CCSP expression during endotoxin-induced lung injury in rats.